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Tektronix 2715, Руководство пользователя

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CATV Measurements

5–60

2715 User Manual

CROSS MODULATION Measurement

The spectrum analyzer has two methods for measuring cross modulation: Time
Domain NCTA (National Cable Television Association) and Frequency Domain.
You can select the method from the CROSS MODULATION measurement menu
(refer to Enable CROSS MODULATION Measurement on page 5–61).

Both methods measure and record the cross modulation in the current channel.
For meaningful calibration, both methods require using the system stimulation
recommended by the NCTA. This stimulation requires the following:

H

All carriers (except the channel under test) must be synchronously modulated
100% with a horizontal rate square wave.

H

The channel under test must carry an unmodulated CW carrier.

The two methods measure cross-modulation effects on the CW carrier in
fundamentally different ways.

The Time Domain (NCTA) method tunes the spectrum analyzer to the visual
carrier frequency, sets ZERO SPAN, and then detects any modulation with an
envelope detector. A Fourier analysis is performed on the output of the detector
to assess the amplitude of the modulation at the horizontal rate. The result is
scaled and reported in units of dBc.

The Time Domain (NCTA) method closely conforms to the recommended NCTA
procedure. This method is often thought to most accurately reflect the level of
visible picture impairment. However,  this may not be the best method for
measuring sideband amplitudes, since cross modulation can also occur as phase
modulation, which the envelope detector used by this method does not detect.

 Therefore, the cross modulation sidebands can have significantly higher
amplitudes than indicated by the Time Domain measurement result. This may
result in picture impairment arising from phase modulation to amplitude
modulation conversion in the asymmetric IF filter of the TV receiver, and may
lead to failure to detect coherent disturbances in excess of legal limits.

NOTE

. The Frequency Domain method is sensitive to the accuracy of the

frequency of the visual carrier when the frequency is defined in the channel table
(refer to Channel Tables on page 5–6). If the channel under test has an
aeronautical offset of 12.5 kHz and the offset is not accounted for in the channel
table, then the cross modulation measurement may not find the 15.73 kHz
sidebands. If the sidebands are not found, the measurement will abort.

The Frequency Domain method reliably detects sidebands arising from either
amplitude modulation or phase modulation (or a combination of both). Also, the
useful measurement range of the Frequency Domain method is significantly
greater than that of the Time Domain method.

Содержание 2715

Страница 1: ...User Manual 2715 Spectrum Analyzer 070 9115 05 This document supports firmware version 2 14 97 and above ...

Страница 2: ...patents issued and pending Information in this publication supercedes that in all previously published material Specifications and price change privileges reserved Printed in the U S A Tektronix Inc P O Box 1000 Wilsonville OR 97070 1000 TEKTRONIX and TEK are registered trademarks of Tektronix Inc ...

Страница 3: ...any other locations This warranty shall not apply to any defect failure or damage caused by improper use or improper or inadequate maintenance and care Tektronix shall not be obligated to furnish service under this warranty a to repair damage resulting from attempts by personnel other than Tektronix representatives to install repair or service the product b to repair damage resulting from improper...

Страница 4: ......

Страница 5: ... Screen 3 1 Connectors Controls and Menus 3 2 SWP TRG Menu Structure 3 11 UTIL Menu Structure 1 of 2 3 12 UTIL Menu Structure 2 of 2 3 13 MRK FREQ Menu Structure 3 13 CATV APPL CATV Measurements Page 1 Menu Structure 1 of 3 3 14 CATV APPL CATV Measurements Page 1 Menu Structure 2 of 3 3 15 CATV APPL CATV Measurements Page 1 Menu Structure 3 of 3 3 16 CATV APPL CATV Measurements Page 2 Menu Structu...

Страница 6: ...15 Mode 5 4 CARRIER LEVEL and AVERAGED POWER Measurement 5 20 CARRIER SURVEY Measurement 5 25 MODULATION DEPTH Measurement 5 28 AURAL FM DEVIATION Measurement 5 32 CARRIER TO NOISE DESIRED to UNDESIRED Measurement 5 35 HUM LFD Measurement 5 40 FREQUENCY RESPONSE 5 43 ADJACENT CHANNEL LEAKAGE Measurements 5 47 CTB and CSO Measurements 5 49 CROSS MODULATION Measurement 5 60 In Channel Response Measu...

Страница 7: ...pendix D Global Resets D 1 Definitions D 1 Reset Cycle Description D 1 Reset Categories D 2 Appendix E External Input and Output E 1 Mains Power E 1 J101 TV Sideband Analyzer and External Tracking Generator Interface E 1 J102 External Trigger E 2 J103 Accessory Connector E 2 J104 Digital Communications Port E 7 Appendix F Accessories and Options F 1 Accessories F 1 Options F 3 Glossary and Index ...

Страница 8: ...trols 3 7 Figure 3 8 Resolution BW and Sweep Control 3 8 Figure 3 9 The 2715 Back Panel 3 10 Figure 4 1 Example of a Waterfall Display 4 25 Figure 4 2 Typical Plotter Output Showing TV Channel Spectrum 4 34 Figure 5 1 CATV MEASUREMENTS Menu 5 4 Figure 5 2 Channel 2 of the STD channel table selected for edit with menu set to change SCRAMBLED toggles between YES NO 5 7 Figure 5 3 Channel with FINISH...

Страница 9: ...nd Maximum Observed Deviation 6 55 Figure 6 15 Video Field Using Internal or TV Field Triggering 6 84 Figure 6 16 Video Signal Using Continuous Horizontal Line Triggering 6 86 Figure 6 17 Video Signal Using Knob Selectable Horizontal Line Triggering VITS Visible 6 87 Figure A 1 Typical Accuracy Limits for Carrier to Noise Measurement A 7 Figure A 2 Typical Accuracy Limits for CTB Measurement A 7 F...

Страница 10: ...GPIB Connector Pin Assignments E 7 Figure E 4 RS 232 C Connector Pin Assignments E 8 Figure E 5 9 Pin Female to 9 Pin Female Null Modem Cable E 9 Figure E 6 9 Pin Female to 25 Pin Female Null Modem Cable E 10 Figure E 7 9 Pin Female to 25 Pin Male Extension Cable E 11 ...

Страница 11: ...3 Frequency Amplitude Related Characteristics A 13 Table A 4 Amplitude Related Characteristics A 14 Table A 5 Input Output Signal Characteristics A 17 Table A 6 Power Requirements A 19 Table A 7 Supplementary Characteristics Due to Options A 19 Table A 8 General Characteristics A 20 Table A 9 Environmental Characteristics A 21 Table A 10 Physical Characteristics A 22 Table A 11 Certifications and ...

Страница 12: ...Table of Contents viii 2715 User Manual ...

Страница 13: ...e input or output terminals of the product ensure that the product is properly grounded Observe All Terminal Ratings To avoid fire or shock hazard observe all ratings and marking on the product Consult the product manual for further ratings information before making connections to the product The common terminal is at ground potential Do not connect the common terminal to elevated voltages Do not ...

Страница 14: ...ION Caution statements identify conditions or practices that could result in damage to this product or other property Terms on the Product These terms may appear on the product DANGER indicates an injury hazard immediately accessible as you read the marking WARNING indicates an injury hazard not immediately accessible as you read the marking CAUTION indicates a hazard to property including the pro...

Страница 15: ...ence in making cable television related measurements Standards and Conventions Used Most terminology is consistent with standards adapted by IEEE and IEC Abbreviations used in the instrument and in the documentation are consistent with ANSI Y1 1 1972 Copies of the ANSI and IEEE standards can be ordered from the Institute of Electrical and Electronic Engineers Inc Change History Information Changes...

Страница 16: ...e To remind you of this AUTO SWEEP is shown in the top center of the box The parentheses mean the enclosed item is not part of the normal on screen readouts Six appendices a glossary and an index contain information about a number of topics useful but not essential to spectrum analyzer operation Introduction contains a brief description of spectrum analysis and reviews the characteristics of the T...

Страница 17: ...scriptions and categories of the various reset procedures for the instrument settings Appendix E External Input and Output explains the procedure to get signals in and out of the back panel of your spectrum analyzer Configurations for interconnect cables are also discussed Appendix F Accessories Options describes all standard and optional accessories and options currently available for the 2715 If...

Страница 18: ...Preface xiv 2715 User Manual ...

Страница 19: ...Introduction ...

Страница 20: ......

Страница 21: ...easurements on graph paper with one centimeter divisions making each division equal 1 MHz the span division of the resulting plot is 1 MHz division If you stop tuning the receiver no longer spans a range of frequencies but is fixed at the currently selected frequency it is in zero span mode The output of the receiver depends on the signal coming through the IF filter at the selected frequency If y...

Страница 22: ...channel In nonCATV mode measurement parameters can be controlled directly with dedicated keys You can display a spectrum by using only three controls Call up menus enable you to automate operations such as bandwidth or carrier to noise ratio measurements and to directly enter front panel control settings Measurement parameters and results are displayed on screen To increase measurement flexibility...

Страница 23: ...nalyzer are guaranteed only for the factory default YIG settling delay time In service measurement capability includes measurement of C N CSO and ICR on NTSC and PAL signals only Gating hardware in the 2715 Spectrum Analyzer allows these measurements to be made on normal modulated TV signals without disruption to the TV program in progress Since gated measurement techniques have advantages and dis...

Страница 24: ...Introduction 1 4 2715 User Manual ...

Страница 25: ...Getting Started ...

Страница 26: ......

Страница 27: ...y the shipping container Test spectrum analyzer operation using the System Checkout procedure on page 2 4 If damage or defects are discovered or if components are missing notify your local Tektronix field office or representative Packaging and Storing In the event that the equipment must be returned to a Tektronix Service Center carefully package it in the original shipping container Use the vinyl...

Страница 28: ... in 177 9 mm Contact your local Tektronix field office or representative for additional information The 2715 is equipped with a plastic front panel cover to protect it from mechani cal damage The cover should always be used when transporting the 2715 To remove the cover place the 2715 on its back feet then simultaneously pull out and up slightly on each side of the cover Regardless of where the sp...

Страница 29: ...nvironment However in the field or during abnormal conditions you might have to connect temporary power Be certain that any power source connected to the 2715 applies less than 250 VACRMS between conductors or between either conductor and ground To avoid damage to the source ensure that it is rated for at least 120 W operation H Do not allow moisture dust or other contaminants inside the case Elec...

Страница 30: ... hear a few beeps as the 2715 performs its power up self test When power is applied to the 2715 it initializes its front panel controls to settings stored in memory If the instrument has been used before those settings may be user defined see User Defined Power Up Settings on page 6 62 If no user defined settings exist the 2715 defaults to the factory power up settings that are permanently stored ...

Страница 31: ...d a new normalization should be carried out Normalization ensures the utmost accuracy when making measurements We suggest that whenever maximum accuracy is required you allow your instrument to reach a stable operating temperature in the environment in which the measurements will be carried out and then perform a normalization before making the measure ments Perform a normalization to ensure the c...

Страница 32: ... Level 68 8 dBmV Figure 2 1 Display with Factory Default Power Up Settings The displayed spectrum represents the noise floor of the spectrum analyzer The noise floor is the amplitude of the noise generated internally by the spectrum analyzer itself and passed through the resolution bandwidth filter Narrowing the resolution bandwidth lowers the noise floor because noise power is directly proportion...

Страница 33: ...acter wide by 16 character high text screen Not all of the text fields are displayed all the time and you can turn the text screen on and off by pressing READOUT The top portion of the text screen contains two data readout columns that are present whenever the text screen is turned on The readouts show spectrum analyzer settings or measurement results Figure 2 2 shows the data normally displayed i...

Страница 34: ...electable features H A numeric keypad permits selection of menu options and entering of critical measurement parameters H Terminator buttons in the keypad block designate the units for numeric entries with a single keystroke H An immediate entry mode that enables you to enter arbitrary values for the channel frequency span and reference level directly from the keypad H Red LED function status indi...

Страница 35: ...e of buttons that carried out the action is typical of operations performed on the 2715 8 Press VID FLTR to observe the toggle action The red video filter LED illuminates and the trace shrinks vertically as the filter turns on and averages the noise 9 Press VID FLTR again The noise spectrum expands to its original size as the filter is turned off and the LED goes out The 2715 can emit tones under ...

Страница 36: ...d below the REF LEVEL key 11 Press the AUTO RES BW key 12 Press INPUT to call up the Input Menu Item 9 specifies a CAL SIG 100MHz 18 8DBMV The calibrator is a CW signal with a fundamental frequency of 100 MHz at an amplitude of 18 8 dBmV 30 dBm Higher order harmonics at lower levels are also present Item 9 toggles the calibrator on and off 13 Press 9 to turn the calibrator on The screen reverts im...

Страница 37: ...rs at left center of the screen The CHAN indicator tells you that you can enter the channel number directly from the keypad This is done by keying in a permissible number followed by the W terminator key labeled CHAN Select an active channel channel 8 for this exercise 5 Press keypad numbers corresponding to the desired channel The numbers you press appear on screen to the right of CHAN If you mak...

Страница 38: ...ll up the CARRIER LEVELS menu 8 Press 0 to select run the Carrier Levels The 2715 starts the measurement routine much like performing a center measure on the visual and aural carriers When the measurement is finished the 2715 returns to the spectral display Two lines near center screen display the measurement results One line displays the visual carrier amplitude and frequency in absolute values a...

Страница 39: ...T POWER UP settings The factory defaults set the RF attenuation to 50 dB This affords the most protection to the spectrum analyzer because any signal at the input undergoes maximum attenuation before reaching the power sensitive mixer circuit We recommend that you use this setting when connecting unknown signals to the spectrum analyzer 2 Press CATV APPL 8 0 to disable the CATV mode 3 Press MAX th...

Страница 40: ...gray function block and are shown in Figure 2 4 The three primary controls and the FREQ MKRS knob to the left are the controls you will use most often In general you can make most measurements with only these controls although you will find that other controls and menu features enable you to make many measurements more quickly and conveniently Decrease Change span div in 1 2 5 sequence Selects fre...

Страница 41: ...on readouts have decreased 30 dB the reference level is 38 8 dBmV and the RF attenuation is 20 dB Normally the arrow keys change the reference level 10 dB per press but in FINE mode the value changes 1 dB per press Another method is to set the reference level to 20 8 dBmV less than half a division above the expected signal ampli tude We choose this value for the following reasons H Signal amplitud...

Страница 42: ...ered The Y key can represent units of kHz or dB Because you selected an entry mode immediate reference level entry that requires decibels and because the factory default unit is dBmV the spectrum analyzer correctly interprets the currently displayed entry as 20 8 dBmV If the currently selected reference level units had been dBm or dBW the 2715 would have interpreted your entry correctly when you p...

Страница 43: ...equires a frequency the 2715 correctly interprets the currently displayed entry as 6 MHz If a time or voltage unit had been required the 2715 would have interpreted your entry as 6 ms or 6 mV respectively The span now is set to 6 MHz and the ninth harmonic of the calibrator signal is centered on screen at 900 MHz You may have noticed that the resolution bandwidth changed to 1 MHz This demonstrates...

Страница 44: ...ears and then entering the correct value 15 Press X after the correct number has been entered This key can represent units of MHz ms or mV Had you wanted to set the frequency to 101 kHz you would have pressed Y This method of changing center or start frequency is most useful when large changes are required or if you know ahead of time exactly what frequency is required The span is now set to 6 MHz...

Страница 45: ...ncy is 100 MHz and the signal peak is 0 2 division below the reference level so its amplitude is 18 8 dBmV as shown in the following equation 20 8 dBmV ref level 0 2 div 10 dB div 18 8 dBmV Using only the frequency span and reference level controls you have verified the basic operation of the 2715 and determined the frequency and amplitude of its calibrator signal ...

Страница 46: ...Getting Started 2 20 2715 User Manual ...

Страница 47: ...Operating Basics ...

Страница 48: ......

Страница 49: ...n area is available for the sweep display but contents of the text screen are placed in predetermined locations Figure 3 1 shows the text screen layout used in the spectral display mode When the optional Display Title line is not used rows 2 through 11 and rows 13 14 and 15 move up one Display Title optional Center Freq Start Freq RF Atten Mkr Freq Counter Freq Reference Level Vid Fltr BW Marker a...

Страница 50: ...rompts general information and data entries LINE SCREEN CONTENT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Figure 3 2 Layout of the Text Screen in the Menu Display Mode Connectors Controls and Menus Most of the spectrum analyzer front panel controls are located in function blocks that are denoted by their borders or background colors Each block contains related controls The central gray colored block ...

Страница 51: ...ectrum Analyzer Menus sections Figure 3 3 The Frequency Marker Function Block In the normal spectral display mode the knob changes the center or start frequency by 0 02 of the span div per click In programmed or tabular tuning modes frequency is changed by the designated tuning increment per click In ZERO SPAN frequency is changed by a percent of the resolution BW per click see Selecting the Tunin...

Страница 52: ...right Signals must be above the detection threshold see Setting the Signal Threshold on page 6 22 Figure 3 4 Fundamental Analyzer Controls Selects the channel number immediate entry mode when CATV mode is active CHAN appears on the screen at left center Enter the desired channel from the keypad terminate with W In nonCATV mode it selects the center or start frequency for immediate entry mode FREQ ...

Страница 53: ...increment mode and by the designated tuning increment in other modes SPAN DIV change in a 1 2 5 sequence from 1 kHz to 180ĂMHz REF LEVEL change 1 dB or 10 dB per step depending on REF LVL STEP setting Shortcuts respectively to the zero span and maximum span settings The keys are toggles one press activates the setting the second returns to the span used prior to the first press ZERO SPAN no freque...

Страница 54: ...ecimal point in numeric entries and can be used as a period in label and title entries The backspace key erases the last character pressed in data entry modes and backs up one menu level when menus are active Figure 3 6 Display Register Control Pressing A B C or D when SAVE ENABLE is not armed turns its respective register on and off for display When the register is displaying data saved or curren...

Страница 55: ... hold mode When MAX HOLD is enabled the A and B registers retain the largest signal observed unless they contain saved waveforms The LED below the key lights when MAX HOLD is active Figure 3 7 Vertical Scale and Other Controls This area of the front panel contains the following controls 10 5 1 Press repeatedly to cycle the vertical scale in a 10 5 1 10 sequence in LOG logarithmic display mode LIN ...

Страница 56: ...or mode Outer knob controls volume of the AM and FM demodulators Lights when the AM or FM demodulators are active to indicate that the outer knob of the LEVEL control sets the audio volume See DEMOD on page 6 56 Normally the spectrum analyzer smooths the detected signal with a video filter having a bandwidth equal to the resolution bandwidth The filter bandwidth is indicated in the right hand read...

Страница 57: ... Pressing SWEEP AUTO also exits single sweep mode but preserves the sweep rate selection mode The LEDs below the keys are lit when the automatic mode is selected When toggling out of the automatic mode the resolution BW and sweep rate remain as they were until manually changed When toggling into the automatic mode the spectrum analyzer selects the resolution bandwidth and sweep rate appropriate to...

Страница 58: ...ernal Trigger Input BNC Female Trigger Level u0 1 Vt 50V Peak Duration u 0 1ms Ventilation Openings DO NOT BLOCK Accessory Connector DB 9 Female v TRACE ROT VERT POS HORIZ POS Option 15 First LO Output SMA Female 50W For Model 1405 TV Sideband Analyzer or 2707 External Tracking Generator v Figure 3 9 The 2715 Back Panel ...

Страница 59: ...re used for servicing information about these submenus is in the optional 2715 Spectrum Analyzer Service Manual Refer to Table F 2 Optional Accessories on page F 1 for the part number of the service manual 0 FREE RUN 1 INTERNAL 2 EXTERNAL 3 LINE 4 TV LINE 5 TV FIELD SWEEP MENU 6 SWEEP RATE 7 MANUAL SCAN 8 SYNC POLARITY 9 SETUP TABLE HORIZONTAL LINE TRIGGERING 0 CONTINUOUS 1 KNOB SELECTABLE 2 KEYPA...

Страница 60: ...ONFIG 1 SCREEN PLOT CONFIGURATION 2 PRINTER CONFIGURATION 3 INSTRUMENT CONFIGURATION 4 REAL TIME CLOCK SETUP 5 STORED SETTINGS PROTECT 6 FILE SYSTEM DIRECTORY 7 PROTECT FILE 9 INSTALLED OPTIONS DISPLAY 0 GPIB 2 RS 232 0 STATUS 1 BAUD RATE 2 DATA BITS 3 PARITY 4 EOL 5 FLOW CONTROL 6 ECHO 7 VERBOSE 0 COMM PORT 1 PLOTTER LANGUAGE 2 PLOT SPEED 3 PLOTS PER PAGE 5 GRATICULE LINES ON PLOT 0 AUDIO ALERT 1...

Страница 61: ...TS 5 TOGGLE VD DAC LO HI 6 VD DAC TO VIS CARR 7 AFC TOGGLE 8 GATE TOGGLE 9 QUERY LOCK STATUS 0 SETTINGS VERIFY 1 FILE SYSTEM MENU 2 YIG SETTLE DELAY Factory troubleshooting aids not discussed in this manual 1 Option 50 and Option 75 only Factory troubleshooting aids not discussed in this manual 0 THRESHOLD 1 PROGRAMD TUNING INC 2 KNOB FUNCTION 3 MARKER TO REFERENCE LEVEL 4 MOVE MARKER TO NEXT PEAK...

Страница 62: ...EY TEST MODES 0 ACCURATE FREQUENCY AND AMPL 1 ACCURATE AMPLITUDE ONLY 2 FAST AMPLITUDE ONLY 0 ON OFF 1 ATTEN AMPL ENTRY TEST MODES 0 ACCURATE FREQUENCY AND AMPL 1 ACCURATE AMPLITUDE ONLY 2 FAST AMPLITUDE ONLY 0 ON OFF 1 ATTEN AMPL ENTRY 0 RUN MODULATION DEPTH 1 STORE CURRENT RESULTS 2 DISPLAY RESULTS 3 PRINT CURRENT RESULTS 4 PRINT STORED RESULTS 5 SET UP ADJUSTMENT MODE 6 ENTER ADJUSTMENT MODE 9 ...

Страница 63: ...ESPONSE TEST MODES 0 NO REF 1 WITH REF SWEEP RANGE 2 START FREQUENCY 3 STOP FREQUENCY 4 USE DEFAULT START STOP TEST MODES 0 NO REF 1 WITH REF REFERENCE ACQUISITION 2 START FREQUENCY 3 STOP FREQUENCY 4 USE DEFAULT START STOP 5 ACQUIRE NEW REFERENCE 6 STORED REFERENCE MENU 7 EDIT CURRENT REFERENCE NAME Displayed only if a reference has been acquired CATV APPL CATV Measurements Page 1 Menu Structure ...

Страница 64: ... 0 EXIT CATV MEASUREMENT MODE 1 CHANNEL TABLE 2 SKIP CHANNEL 3 ALL CHANNELS 4 SITE 5 OPERATOR 6 REF LEVEL UNIT 7 EDIT CHANNEL TABLES2 8 REMOVE ALL STORED RESULTS 9 LEAVE CATV MEASUREMENTS SETUP 0 STD 1 HRC 2 IRC 3 User Defined 4 User Defined 5 User Defined 6 User Defined 7 User Defined 8 User Defined 9 User Defined CATV APPL CATV Measurements Page 1 Menu Structure 3 of 3 To CATV APPL CATV Measurem...

Страница 65: ...NT RESULTS 2 DISPLAY RESULTS 3 PRINT CURRENT LEVELS 4 PRINT STORED RESULTS 5 SET UP CSO 6 DIGITAL ANALOG 7 IN SERVICE 9 LEAVE CSO TEST MODES 0 INTERACTIVE 1 AUTO 2 AUTO PAUSE FOR CARRIER OFF 3 SINGLE SWEEP 4 CONTINUOUS 5 SET UP TEST FREQUENCIES AND CONTINUOUS MODE PRMTRS TEST FREQUENCIES 0 User Defined 1 25000MHZ Default 1 User Defined 750 000KHZ Default 2 User Defined 3 User Defined 750 000KHZ De...

Страница 66: ...N CHAN RESP 6 TEST SIGNAL LINE NUMBER 7 IN SERVICE 9 LEAVE IN CHAN RESP TEST MODES 0 INTERACTIVE 1 AUTO PAUSE FOR SIGNAL ON TEST FREQUENCIES 2 User Defined 500 000KHZ Default 3 User Defined 500 000KHZ Default 4 User Defined 1 25000MHZ Default 5 User Defined 2 00000MHZ Default 6 User Defined 3 00000MHZ Default 7 User Defined 3 75000MHZ Default 8 USE DEFAULT TEST FREQUENCIES To CATV APPL CATV Measur...

Страница 67: ...SUREMENT MODE 9 SETUP TABLE 0 BEGIN FREQ 1 END FREQ 2 START TEST 3 DISPLAY RESULTS CATV APPL Applications Menu Structure 0 DB DOWN FOR BW MODE 1 NORM BW FOR C N 2 NOISE NORM D BW 3 PERCENT OCCUPIED BW 0 OFF 1 AM DEMODULATOR 2 FM DEMODULATOR 3 BROADCAST AM VIDEO 9 VIDEO MONITOR SETUP 0 VIDEO DETECT MODE 1 SYNC POLARITY 2 VIDEO POLARITY DEMOD Menu Structure ...

Страница 68: ...E MODE 2 TITLE MODE EDIT 3 PLOT LABELING 4 PLOT LABELING EDIT 1 ON OFF 2 VALUE ENTRY 3 DISPLAY LINE TO MARKER 4 LIMIT DETECTOR 0 User Defined 1 User Defined 2 User Defined 3 User Defined 4 User Defined 5 User Defined 6 User Defined 7 User Defined 8 User Defined 9 USER DEF PROGRAM UTILITIES 0 ACQUIRE KEY STROKES 1 TITLE EDIT 2 WAIT FOR END OF SWEEP 3 DISPLAY MESSAGE 4 PAUSE FOR USER DEF KEY 5 CONTI...

Страница 69: ...9 DBUV M SETUP INPUT Menu Structure 0 ON OFF 1 ATTEN AMPL ENTRY 0 EDIT ANTENNA TABLE 1 User Defined 2 User Defined 3 User Defined 4 User Defined 5 User Defined 6 MEASUREMENT DIST 7 SAVE RESULTS IN WFM 9 MARKER DISPLAY 0 BEGIN EDIT 1 TITLE EDIT 2 STORE 3 LOAD 4 DELETE 5 PRINT 6 ANTENNA SETUP 1 START FREQUENCY 2 STOP FREQUENCY 3 INC FREQUENCY 4 REFERENCE DISTANCE Not available in CATV Measurements M...

Страница 70: ...Operating Basics 3 22 2715 User Manual ...

Страница 71: ...Dedicated Controls ...

Страница 72: ......

Страница 73: ...ments easily and conveniently Fundamental Operations Getting Started described the amplitude and frequency measurement of a continuous narrow band signal the calibration signal using only three controls This section will repeat the initial measurement but this time with the CHAN FREQ SPAN DIV REF LEVEL and associated controls contained in the gray colored central function block These controls are ...

Страница 74: ...n press b to the right of SPAN DIV several times to decrease the span div to 20 MHz1 This causes the 2715 to zoom in on the spectral display 7 Now press y until the span div increases to 180 MHz Watch the spectral display zoom out just as though it was moving away from you The up arrow increases the span div compressing or squeezing the spectrum together The down arrow decreases the span div and e...

Страница 75: ...ry disappears and then entering the correct value Pressing a terminator button W X Y or Z determines the units and enters the data X can represent units of MHz ms or mV Because the immediate span div entry mode requires a frequency the 2715 correctly interprets the currently displayed value as 33 3 MHz when you press X If a time or voltage unit had been required the 2715 would have interpreted you...

Страница 76: ... The signal amplitude decreases and the noise increases as you tune away from the calibration signal The noise generated internally by the 2715 has a time varying random amplitude In the zero span mode the 2715 does not sweep the frequency spectrum Rather the local oscillator remains at a fixed frequency so that the resolution bandwidth filter brackets the designated center frequency Because the d...

Страница 77: ...e X Y or Z In the nonCATV mode CHAN FREQ the associated y and b and all the terminator keys exclusively control frequency The nonCATV mode is enabled by pressing CATV APPL 8 0 For instance to select channel 8 in the specified table do the following steps 4 Press 8 W The numbers appear on the screen to the right of CHAN If you make a mistake correct it any time prior to pressing W by repeatedly pre...

Страница 78: ...e used to change the normal center or start frequency as discussed in the following example 10 Press y adjacent to CHAN FREQ The frequency changes by channel allocation width of the currently selected channel table 6 MHz for the STD HRC and IRC channel tables If you had previously selected a channel by entering a frequency value that is not centered about the channel allocation width the first inc...

Страница 79: ...ct it any time prior to pressing the MHz terminator by repeatedly pressing BKSP until the incorrect number disappears and then enter the correct value Pressing a terminator key X Y Z determines the units and enters the data X can represent units of MHz ms or mV Because the frequency immediate entry mode requires a frequency the 2715 interprets the currently displayed value as 1 25 MHz when you pre...

Страница 80: ...ough the 2715 low frequency specification is 9 kHz Your entry can contain up to 25 characters but regardless of how many you enter the 2715 attempts to control frequency to the nearest hertz and the frequency is displayed at the top of the left hand data column to 1 of the span div 6 Press CHAN FREQ to enter the immediate entry mode 7 Press 1 2 5 X to set the center frequency to 1 25 MHz The numbe...

Страница 81: ...evel Instead the reference level decreases changes in the direction indicated by the arrow key to 28 8 dBmV and the attenuation to 10 dB The signal only appears larger because the reference level has been lowered 10 dB and now represents a signal level of 28 8 dBmV 10 dB or one division greater than the calibration signal 2 Press y adjacent to REF LEVEL to reduce the on screen signal height one di...

Страница 82: ...th of a dB 4 Press 2 1 3 Y to set the reference level to 21 3 dBmV The numbers you type appear on screen to the right of REFL If you make a mistake you can correct it any time prior to pressing Y by repeatedly pressing BKSP until the incorrect number disappears and then typing the correct value Pressing a terminator key only Y or Z in this case determines the units The Y key can represent units of...

Страница 83: ...erence level to 38 8 dBmV Enhanced Versatility The first part of this section covered the fundamental controls of the 2715 This second part covers the remaining controls and how they enhance your ability to make accurate spectral measurements easily and conveniently We cover how to control the resolution bandwidth vertical scale factor and sweep speed We show how to use display storage and marker ...

Страница 84: ...maximum bandwidth filter to ensure enough bandwidth for the video signal In other cases you may want to select a very narrow resolution bandwidth in order to resolve signal sidebands or intermodulation distortion products The RES BW arrow keys enable you to select resolution bandwidths of 300 Hz 1 kHz 3 kHz 10 kHz 30 kHz 100 kHz 300 kHz 1 MHz and 5 MHz in the 2715 It is important to know how far s...

Страница 85: ... signal is moved past the filter it maps the shape of the resolution filter What you see is the spectral shape of the filter rather than that of the calibration signal This means that on unmodulated signals a resolution bandwidth filter that is too wide can artificially broaden the displayed spectrum although the signal peak remains accurate 10 Repeatedly press b in the RES BW function block to na...

Страница 86: ...UTO Channel Name CH nn CALIBRATOR A video filter is a postdetection filter sometimes referred to as a noise averaging filter used to reduce noise in the displayed spectrum to its average value making low level signals more easily detectable Normally the 2715 uses a video filter about as wide as the resolution bandwidth This limits postdetection noise but does not significantly alter the displayed ...

Страница 87: ...ower portion of the spectral display appears By filtering the noise it is sometimes possible to reveal low level signals that are in the noise This is the primary reason for using a video filter The signal peaks at 700 MHz 800 MHz and 900 MHz the seventh eighth and ninth harmonics of the calibration signal should now be visible There are small differences from instrument to instrument but you shou...

Страница 88: ...nal peak is now five divisions down and the readout says 1 dB The primary use for this feature is to more accurately read displayed signal peaks 3 Press 10 5 1 once again to restore the 10dB setting LIN The second key in the VERT SCALE function block is also toggle action It converts the vertical scale from logarithmic to linear and back again 4 Ensure that the calibration signal is centered and t...

Страница 89: ...you may want to vary the sweep rate for a better view of the signal 1 Ensure that the calibrator is turned off and enter the zero span mode The currently selected sweep rate is displayed on screen as the horizontal scale factor in zero span mode and has units of time division in the spectral mode view the sweep rate by pressing SWP TRIG The sweep rate readout indicates 50MS ZSPAN 50 ms div in zero...

Страница 90: ...ase the sweep speed and notice the signal peak decrease and shift to the right This condition occurs when sweeping too fast for a given resolution BW and demonstrates how measurement errors can occur The resolution filter is sweeping so fast that its output does not have time to reach steady state 9 Reselect ZERO SPAN The UNCAL message disappears because in the zero span mode the filter is not bei...

Страница 91: ...ep Other controls except AUTO in the SWEEP function block operate normally and signals at the input to the 2715 are treated just as they would be otherwise Pressing AUTO in the SWEEP function block exits from the single sweep mode When a sweep begins will depend on how the 2715 is triggered The factory default mode is free run this is the mode the 2715 currently should be in 15 Set the resolution ...

Страница 92: ...le sweep mode is useful when you want to prevent a succeeding sweep from overwriting a trace you just acquired or to capture the characteristics of intermittent signals There is a dual concentric shaft LEVEL control below the FREQ MKRS knob The inner knob controls the triggering level when the 2715 is in internal external or line trigger modes just as the equivalent control does on a conven tional...

Страница 93: ...ate the display registers A register s contents are displayed only when it is active red LED lighted although it still contains saved data as long as its green LED is lighted 1 Press C to turn on the C register The only change that might be apparent is an increase in intensity since the 2715 is now displaying the C trace on top of the D trace 2 Press A and B to turn on the A and B registers There ...

Страница 94: ...sed when CATV mode is activated at power up during a reboot cycle UTIL 5 0 9 or when it is reactivated after having been disabled 5 Press SAVE ENABLE to manually save a waveform The red LED below SAVE ENABLE lights This indicates that the SAVE function is armed 6 Press A to save into the A register what is presently being displayed The green LED below A lights but observe that the A register was t...

Страница 95: ...deactivate the C register and activate A The A green LED turns off indicating there is nothing stored in the A register The register remains active but the displayed spectrum is now updated during each sweep The on screen readouts are stored along with the sweep Since the 2715 displays only one group of readouts at a time the readouts for the highest priority register are displayed when multiple r...

Страница 96: ...he register status LEDs light and four traces appear Registers A B and C must be cleared before the 2715 allows you to enter the waterfall mode because the waterfall mode uses all four registers This is a safeguard to prevent accidental overwriting of previously saved data If you attempt to enter this mode without first clearing the registers you receive an error message Look at Figure 4 1 D is th...

Страница 97: ...e traces 27 Turn off the A and C registers 28 Turn off B and D registers 29 Turn A and C registers back on You can view any all or none of the registers Turn them all off and the analog display reappears However the 2715 is still in waterfall mode You cannot selectively erase a register or store new data in it without first exiting from the waterfall mode 30 Turn on all registers 31 Press SAVE ENA...

Страница 98: ...ored values 36 Activate the D register Note that the waveform in the D register waveform without MAX HOLD is always less than the A register waveform Recording the peak signal excursions observed during a large number of sweeps using the MAX HOLD feature yields an estimate of the maximum signal values It can also be very useful for determining maximum signal amplitude during transient condi tions ...

Страница 99: ...on the highest priority waveform 1 Press MKR OFF to activate the marker The sweep does not change but the RF attenuation and video filter readouts have been replaced by approximate marker frequency and amplitude readouts such as the following M 100 0MHZ M 18 8DBMV The M preceding the readouts represent the amplitude and frequency of the signal at the marker position 2 Turn the FREQ MKRS knob sever...

Страница 100: ...ta marker mode is turned on 8 Turn the tuning knob clockwise Now you can see both markers One remains at the original marker position while the position of the second is controlled by the knob The right column indicates the difference denoted by the letter D preceding the readouts in frequency and amplitude between the two marker positions 9 Increase the span to 50 MHz div 10 Use the tuning knob t...

Страница 101: ...er mode two if in single mark er mode to exit the marker mode and return to the normal RF attenuation and video filter readouts 15 Turn off the video filter CTR MEAS TRKG 140 0MHz AUTO SWEEP ATTN 40DB 28 8DBMV VF WIDE 50 0MHz 10 DB 5MHz RBW AUTO CALIBRATOR The center measure feature detects the signal peak nearest the marker and above a preset amplitude threshold changing the threshold is discusse...

Страница 102: ...play nonlinearities The center frequency and counter measurements are also equally accurate but in general the counter readout is more precise 20 To look closely at the calibration signal third harmonic place the marker near the third harmonic approximately 280 MHz 21 Press CTR MEAS TRKG The calibration signal third harmonic is now the new center frequency and its frequency and amplitude are displ...

Страница 103: ... continuously repeats the center measure operation On each sweep the signal nearest midscreen is remeasured and recentered This is useful for keeping a slowly varying or jittering signal centered for close observation 26 Press CTR MEAS TRKG twice to activate signal track The term TRKG appears in center screen indicating that the 2715 is in the signal track mode If you turn the tuning knob while a ...

Страница 104: ... the tracking mode and turn off the markers Arrow Keys You can use the arrow keys to move the marker from one peak to another 35 Center the calibration signal 36 Turn on the marker 37 Press MKR The marker jumps to the second harmonic peak 38 Press again 39 The marker jumps to the third harmonic 40 Now press MKR a The marker jumps in the other direction MKR a and MKR move the marker to the next sig...

Страница 105: ...ls will be covered briefly here NOTE Any control settings can be used PLOT Immediately below the VERT SCALE function block is a PLOT button that causes an optional printer or plotter to draw an image of the screen The on screen readouts are plotted on the drawing in the border area so they do not interfere with the waveform If you wish to have graticule lines on the printout you must turn them on ...

Страница 106: ...ard on screen readouts on and off There are two reasons for doing so First it prevents the readouts from overlapping the signal spectrum The following steps illustrate the second reason 1 Initialize the 2715 to the factory power up defaults 2 Enter the analog display mode 3 Press SWEEP y Notice the regularly spaced dark areas in the sweep 4 Press READOUT below the VERT SCALE function block to turn...

Страница 107: ...t to full intensity try reducing the ambient light or shielding the display If the 2715 is used in direct sunlight a contrast enhancing light filter is recommended part of the Travel Line Package Option 33 Rear Panel Trace Adjustments There are three controls TRACE ROTation VERTical POSition and HORIZontal POSition at the upper right of the 2715 rear panel that are used with a built in test displa...

Страница 108: ...Dedicated Controls 4 36 2715 User Manual ...

Страница 109: ...CATV Measurements ...

Страница 110: ......

Страница 111: ...raged power measurement H Survey of system analog visual and aural carrier levels and frequencies measure ment plus digital channel averaged power measurement H Depth of modulation measurement H Aural carrier deviation measurement H Visual carrier to noise ratio measurement H Desired to Undesired signal ratio measurement on digital channels H Hum low frequency disturbance measurement H System freq...

Страница 112: ...ignal dBmV 1 10 30 50 70 100 70 0 60 0 55 2 53 0 51 5 50 0 Remember two 68 dBmV signals total more than 70 dBmV Higher signal levels should be externally attenuated With the exception of Adjacent Channel Leakage ACL these tests are characterized for use in a multichannel environment no preselector or in a single channel environment preselector used ACL is characterized for the single channel envir...

Страница 113: ...2715 At power up the 2715 comes up in the CATV mode tuned to the default power up channel The power up channel is the last active channel when power was turned off or channel T 7 labeled 907 in STD Table 5 4 if NVRAM was erased before the last power down Upon entering the CATV MEASUREMENT MODE the instrument software searches for the visual carrier signal associated with the default power up chann...

Страница 114: ...he 2715 is not already in the CATV mode press CATV APPL 8 0 from the spectral display The firmware centers the channel on the screen then displays the top level PG 1 of the CATV MEASUREMENTS menu The menu resides on two pages You can toggle between the menu pages by pressing 9 from either page See FigureĂ5 1 Figure 5 1 CATV MEASUREMENTS Menu The 2715 is capable of making certain measurements on TV...

Страница 115: ...l type with the new software Table 5 2 shows the measurements that can be made on each signal type Table 5 2 Signal Type Measurements ea ure e Signal Types Measurements TV FM Pilot Digital Carrier Level X X X Avg Power X Carrier Survey X X X X Modulation Depth X Aural FM Deviation X X Carrier To Noise X X X Desired Undesired X Hum LFD X X X Frequency Response X X X X View Field Modulation X View L...

Страница 116: ...ling Status False VITS None Channels 907 through 913 in the STD factory loaded channel table Table 5 4 represent channels T 7 through T 13 There are a number of different television standards worldwide that differ in video modulation polarity In negative video modulation maximum carrier power occurs during the sync tips In positive video modulation maximum carrier power occurs during white program...

Страница 117: ...o NOTE If you assign a channel frequency above 1 8 GHz the channel table will be unusable by the Cable TV RF Measurements Software Use the front panel buttons to make the changes and back space button BK SP to remove the changes one character at a time Use ABORT ALL to undo all changes back to when FINISH was last executed and use UNDO CHAN to undo all changes back to when the channel was selected...

Страница 118: ...O any line number USE KEYPAD W ENTER Z AUTO ICR LINE NONE any video line number USE KEYPAD W ENTER Z NONE WHITE LINE NONE any video line number USE KEYPAD W ENTER Z NONE POLARITY VIDEO SYNC NEG NEG NEG POS POS NEG POS POS USE MKR ARROWS TO EDIT5 FINISH N A X STORE TABLE AND EXIT UNDO CHAN N A Y UNDO CHANNEL CHANGES ABORT ALL W CONFIRM ABORT Z CANCEL Z ABORT ALL TABLE CHANGES 3 The last line of tex...

Страница 119: ...lected The FINISH selection shown in Figure 5 3 ends the editing session and goes back to the CATV MEASUREMENTS SETUP menu The table of edited data is copied into NVRAM and becomes the master copy Upon returning to the spectral display if the channel displayed currently was edited during the session the screen will reflect the changes The UNDO CHAN selection repaints the screen with all the values...

Страница 120: ... 13 00 19 00 25 00 31 00 37 00 43 00 11 5 17 5 23 5 29 5 35 5 41 5 47 5 2 3 4 5 6 55 25 61 25 67 25 77 25 83 25 59 75 65 75 71 75 81 75 87 75 95 96 97 98 99 91 25 97 25 103 25 109 25 115 25 95 75 101 75 107 75 113 75 119 75 14 15 16 17 18 19 20 21 22 121 25 127 25 133 25 139 25 145 25 151 25 157 25 163 25 169 25 125 75 131 75 137 75 143 75 149 75 155 75 161 75 167 76 173 75 7 8 9 10 11 12 13 175 2...

Страница 121: ...5 323 75 329 75 335 75 341 75 44 45 46 47 48 49 50 343 25 349 25 355 25 361 25 367 25 373 25 379 25 347 75 353 75 359 75 365 75 371 75 377 75 383 75 51 52 53 54 55 56 57 385 25 391 25 397 25 403 25 409 25 415 25 421 25 389 75 395 75 401 75 407 75 413 75 419 75 425 75 58 59 60 61 62 63 64 427 25 433 25 439 25 445 25 451 25 457 25 463 25 431 75 437 75 443 75 449 75 455 75 461 75 467 75 65 66 67 68 6...

Страница 122: ...5 565 25 571 25 577 25 583 25 589 25 557 75 563 75 569 75 575 75 581 75 587 75 593 75 86 87 88 89 90 91 92 93 94 595 25 601 25 607 25 613 25 619 25 625 25 631 25 637 25 643 25 599 75 605 75 611 75 617 75 623 75 629 75 635 75 641 75 647 75 Table 5 5 HRC Channel Visual Carrier Aural Carrier 2 3 4 1 5 6 54 00 60 00 66 00 72 00 78 00 84 00 58 5 64 5 70 5 76 5 82 5 88 5 95 96 97 98 99 90 00 96 00 102 0...

Страница 123: ... 196 50 202 50 208 50 214 50 23 24 25 26 27 28 216 00 222 00 228 00 234 00 240 00 246 00 220 50 226 50 232 50 238 50 244 50 250 50 29 30 31 32 33 34 252 00 258 00 264 00 270 00 276 00 282 00 256 50 262 50 268 50 274 50 280 50 286 50 35 36 37 38 39 40 288 00 294 00 300 00 306 00 312 00 318 00 292 50 298 50 304 50 310 50 316 50 322 50 35 36 37 38 39 40 288 00 294 00 300 00 306 00 312 00 318 00 292 5...

Страница 124: ...6 00 400 50 406 50 412 50 418 50 424 50 430 50 59 60 61 62 63 64 432 00 438 00 444 00 450 00 456 00 462 00 436 50 442 50 448 50 454 50 460 50 466 50 65 66 67 68 69 70 468 00 474 00 480 00 486 00 492 00 498 00 472 50 478 50 484 50 490 50 496 50 502 50 71 72 73 74 75 76 504 00 510 00 516 00 522 00 528 00 534 00 508 50 514 50 520 50 526 50 632 50 538 50 77 78 79 80 81 82 540 00 546 00 552 00 558 00 5...

Страница 125: ...50 634 50 640 50 646 50 Table 5 6 IRC Channel Visual Carrier Aural Carrier 2 3 4 1 5 6 55 25 61 25 67 25 73 25 79 25 85 25 59 75 65 75 71 75 77 75 83 75 89 75 2 3 4 1 5 6 55 25 61 25 67 25 73 25 79 25 85 25 59 75 65 75 71 75 77 75 83 75 89 75 95 96 97 98 99 91 25 97 25 103 25 109 25 115 25 95 75 101 75 107 75 113 75 119 75 14 15 16 17 18 19 20 21 22 121 25 127 25 133 25 139 25 145 25 151 25 157 25...

Страница 126: ...75 29 30 31 32 33 34 253 25 259 25 265 25 271 25 277 25 283 25 257 75 263 75 269 75 275 75 281 75 287 75 35 36 37 38 39 40 289 25 295 25 301 25 307 25 313 25 319 25 293 75 299 75 305 75 311 75 317 75 323 75 41 42 43 44 45 46 325 25 331 25 337 25 343 25 349 25 355 25 329 75 335 75 341 75 347 75 353 75 359 75 47 48 49 50 51 52 361 25 367 25 373 25 379 25 385 25 391 25 365 75 371 75 377 75 383 75 389...

Страница 127: ...9 25 473 75 479 75 485 75 491 75 497 75 503 75 71 72 73 74 75 76 505 25 511 25 517 25 523 25 529 25 535 25 509 75 515 75 521 75 527 75 533 75 539 75 77 78 79 80 81 82 541 25 547 25 553 25 559 25 565 25 571 25 545 75 551 75 557 75 563 75 569 75 575 75 83 84 85 86 87 88 577 25 583 25 589 25 595 25 601 25 607 25 581 75 587 75 593 75 599 75 605 75 611 75 89 90 91 92 93 94 613 25 619 25 625 25 631 25 6...

Страница 128: ...e typically less than 1 H Selection of beat frequencies is more difficult in interactive CSO mode because the gating is not compatible with ordinary video filtering Visually the dominant feature of the resulting screen display is the collection of noise peaks as opposed to the average noise level viewed with appropriate video filtering A technique for minimizing the impact of this effect is sugges...

Страница 129: ...lled to make a suitable compromise between noise and distortion In some instances this may cause an unexpected result The gating hardware used for some of the in service measurements needs a strong signal to perform reliably In a nonflat system weaker signals on the system may fail to meet this requirement because the optimum RF attenuator and preamplifier settings are based on the levels of the s...

Страница 130: ...k visual carrier level averaged power if measuring a digital channel H Visual carrier frequency not available when measuring a digital channel H Intercarrier frequency not available when measuring a digital channel H Visual to aural carrier amplitude ratio not available when measuring a digital channel Three measurement modes allow you to select the trade off between measure ment time and accuracy...

Страница 131: ...r TV channel identifies and measures all carriers in 10 dB div if the channel is a dual aural carrier TV channel sets span to 50 kHz div If you select FAST AMPL measurement mode the 2715 executes the preceding common steps followed by these steps for each carrier in turn H If a dual aural carrier TV channel tunes to the carrier in 50 KHz div and 100 KHz resolution bandwidth Identifies the carrier ...

Страница 132: ... stores the frequency relative to the visual carrier If you measure a digital channel the 2715 executes these steps for each carrier H Recalls base settings if necessary Base settings are the standard settings from which each test is run equivalent to selecting 0 RECENTER CHANNEL xx from the CATV Measurements menu page one H Sets sweep to single sweep mode acquisition mode to sample detect and sel...

Страница 133: ... this example the accurate amplitude measurement mode ACCUR AMPL is selected see menu item 0 4 Press 5 to select a different measurement mode This displays the SET UP CARRIER LEVELS submenu with the following menu choices 0 ACCURATE FREQUENCY AND AMPL 1 ACCURATE AMPLITUDE ONLY 2 FAST AMPLITUDE ONLY 5 Press 0 to select ACCURATE FREQUENCY AND AMPL Note that the asterisk moves to that selection in th...

Страница 134: ...e display means that you are looking at the result of the most recent measurement performed The word STORED appearing at the upper right corner of the display means that you are looking at a stored result for the particular measurement Stored results are displayed in sequence starting with the most recently stored result At this point you can choose to either go ahead and view other previously sto...

Страница 135: ... Intercarrier frequency not available when measuring a digital channel H Visual to aural carrier amplitude ratio not available when measuring a digital channel When the CARRIER SURVEY measurement is initiated the 2715 performs the following steps H Advances to the next unskipped channel in the channel table H Executes a CARRIER LEVELS measurement refer to Carrier Levels Measurement on page 5 20 us...

Страница 136: ...the asterisk moves to that selection in the menu indicating that it is the current selection The CARRIER SURVEY measurement modes are identical to those for CARRIER LEVELS and are described in Carrier Levels Measurement earlier in this section To reduce the run time you may want to tag unwanted channels for omission skipping from the survey To use the Skip Channel selection you must select a chann...

Страница 137: ...p CARR SURVEY CHAN 8 06 JAN 94 STD CHANNEL 2 VISUAL 10 5 DBMV 55 250000MHZ AURAL 15 8DBC 4 500000MHZ CHANNEL 3 VISUAL 9 8 DBMV 61 250000MHZ AURAL 15 4DBC 4 500000MHZ CHANNEL 4 VISUAL 9 5 DBMV 67 250000MHZ AURAL 15 1DBC 4 500000MHZ W CONT Y NEXT Z ABORT CURRENT 12 00 00 Figure 5 5 Typical Carrier Survey Report Screen You can choose to either go ahead and page through all the stored results for the ...

Страница 138: ...ve an RS 232 interface installed in the 2715 You make selections and run the modulation depth test using the CATV MEASUREMENTS submenu MODULATION DEPTH which provides the following choices 0 RUN MODULATION DEPTH 1 STORE CURRENT RESULTS 2 DISPLAY RESULTS 3 PRINT CURRENT RESULTS RS 232 Only 4 PRINT STORED RESULTS RS 232 Only 5 SET UP ADJUSTMENT MODE 6 ENTER ADJUSTMENT MODE 9 LEAVE MODULATION DEPTH W...

Страница 139: ...MODULATION DEPTH 1 STORE CURRENT RESULTS 2 DISPLAY RESULTS 3 PRINT CURRENT RESULTS RS 232 Only 4 PRINT STORED RESULTS RS 232 Only 5 SET UP ADJUSTMENT MODE 6 ENTER ADJUSTMENT MODE 9 LEAVE MODULATION DEPTH 4 Press 0 to run the Modulation Depth measurement After the measurement is complete the instrument displays the current results superimposed on the spectral display 5 Press CATV APPL to display th...

Страница 140: ...NE 87 5 2 CYCLE DELAY 1000MSEC 3 TARGET LINE DURATION 30 0 The VIEW MODULATION MODE provides two choices FIELD or LINE If you select FIELD you view a full field if you select LINE you will view line 17 unless you have specified a VITS line for the channel in the channel table With TARGET LINE selected you can set the target line to the depth of modulation for which you want to adjust The target li...

Страница 141: ...r right hand corner of the screen H Current Sync Tip Voltage value appears in the upper left hand corner of the display If the sync tip voltage varies during the adjustment process the 2715 automatically adjusts the reference level to keep the sync tips at the top of the screen and displays the new sync tip voltage value H User Prompt instructions on how to quit the adjustment mode W or Z To Quit ...

Страница 142: ...DEVIATION which provides the following choices 0 RUN FM DEVIATION INTERACTIVE 1 STORE CURRENT RESULTS 2 DISPLAY RESULTS 3 PRINT CURRENT RESULTS RS 232 Only 4 PRINT STORED RESULTS RS 232 Only 5 SET UP AURAL FM DEVIATION 6 ENTER ADJUSTMENT MODE 9 LEAVE AURAL FM DEVIATION Note that the RUN FM DEVIATION selection indicates the measurement mode in this example interactive is selected You use the SET UP...

Страница 143: ...ion until one of the following occurs H You press W terminates test and saves results H You press Z aborts test and does not save results H A GPIB Device Clear Command DCL is received aborts test and does not save the results H The user selected time limit is reached 7 Computes the result as a mean peak deviation after rejecting widely deviating readings It computes the mean and standard deviation...

Страница 144: ...e 5 1 2 Press 4 to select the AURAL FM DEVIATION measurement menu 3 Press 5 to select SET UP AURAL FM DEVIATION 4 Press 0 to select interactive mode if not already selected as indicated by an asterisk 5 Press 5 and use the keypad to enter and 5 6 Press W to enter selected time sets the measurement time to 0 50 minutes 7 Press BKSP to return to the AURAL FM DEVIATION measurement menu 8 Press 0 to r...

Страница 145: ...not print completely 15 Press 4 to print all stored results of the measurement A printer must be connected to the 2715 16 Press 9 to leave the AURAL FM DEVIATION measurement and return to the CATV MEASUREMENTS menu CARRIER TO NOISE DESIRED to UNDESIRED Measurement The CARRIER TO NOISE DESIRED to UNDESIRED measurement records and displays the visual carrier to noise ratio for the current analog cha...

Страница 146: ...ter on Initially places the marker on the minimum point of the waveform and if necessary changes the reference level setting so that the low point is at least 10 dB above the bottom of the screen b If interactive in service basis is selected returns to frequency and span settings that display the whole channel across the screen Selects 100 kHz RBW and turns the video filter off Enables gating and ...

Страница 147: ...asurement which may cause an inaccurate result If so the inaccuracy is always on the conservative side the actual Carrier To Noise ratio will be better than the measured value If 1000 is added to the result the instrument detected that one or more of the quiet lines found at the start of the test were not quiet at the end of the test If 2000 is added to the result the instrument increased the sign...

Страница 148: ...und in step 5 is included in this calculation 7 The results of the calculation done in step 6 is stored as a desired to undesired ratio The frequency limits that the power was measured within are stored as the signal bandwidth The largest coherent signal found in the undesired measurement is also reported but not stored The following procedure shows how to make a CARRIER TO NOISE or DESIRED to UND...

Страница 149: ...ur ability to locate a low amplitude region for the earnest measurement In this particular situation there is no need for concern when the visual noise level appears to be excessively high In Auto Test Mode you will not be required to do any settings In Auto with Pause for Carrier Off Test Mode you will be prompted to turn off the carrier at some time during the measurement If measuring an analog ...

Страница 150: ...e print function Be sure to select handshaking UTIL 4 0 2 5 to match that expected by the printer or long jobs may not print completely 11 Press 4 to print all stored results of the measurement A printer must be connected to the 2715 12 Press 9 to leave the CARR NOISE DESIRED UNDESIRED menu and return to the CATV MEASUREMENTS menu HUM LFD Measurement The HUM LFD measurement records and displays th...

Страница 151: ...Component The factor of four 4 comes from the following two sources H The two sided nature of the FFT requires that the apparent levels of each harmonic be doubled H The result must be doubled again to obtain the peak to peak harmonic levels since the FFT finds only the peak value of each harmonic component The hum data values are shown in the two readout lines as follows ZZ Z TOTAL HUM XX X F0 YY...

Страница 152: ...od of time the message RESULTS STORAGE COM PLETE is displayed 7 Press 2 to display the results of the last measurement performed A display resembling Figure 5 4 appears showing the current result You can press W to view other previously stored results for this measurement or press Z to stop viewing the results 8 Press 3 to print the results of the last measurement performed A printer must be conne...

Страница 153: ...eference is marked as invalid The instrument will sweep between the start and stop limits specified in this menu apply a digital filter to the resultant sweep and retain the resultant waveform and instrument setup The digital filter is used to smooth the reference to reduce sensitivity to slight frequency errors and differences in program material between the reference sweep and the subsequent fre...

Страница 154: ...e if one exists 0 RUN FREQUENCY RESPONSE CURRENT REFERENCE Site Name Date Start Frequency Stop Frequency user defined name or NONE The reference name appears only if the test mode WITH REF is selected The string SITE NAME DATE START STOP is the default reference name assigned when the reference is acquired You can modify the reference name by selecting item 7 EDIT CURRENT REF ERENCE NAME in the FR...

Страница 155: ...e known 133 3MHZ 22 2DBMV 15 6MHZ 5MHZ RBW FRQ RESP CHAN M 108 6MHZ M 16 5 DBMV 10 DB STD CH 8 Figure 5 6 Typical Frequency Response Display Without Reference The instrument returns to the spectral display Note that the FREQUENCY RESPONSE menu is still active If you press CATV APPL the FREQUEN CY RESPONSE menu will be displayed A more definitive display is acquired by comparing the result to a kno...

Страница 156: ...n is complete the instrument reverts to the spectral display and displays the message REFERENCE ACQUIRED If you want to rename the new reference press CATV APPL 5 7 W and follow the on screen instructions After renaming the new reference press 6 n X where n is a number from 0 to 9 representing a storage register to save it Press CATV APPL 0 to run the frequency response measurement If you want to ...

Страница 157: ...s off ACL measurements may be made beyond the combiner but four channels the two adjacent channels on each side of the channel under test must be turned off before the measurement is made ACL measurements may be selected in the menu to occur on either the lower side upper side or both sides of the channel under test Only the worst ACL encountered is reported If any coherent spurious signals are fo...

Страница 158: ...ment After a short period of time the message RESULTS STORAGE COM PLETE is displayed 8 Press 2 to display the results of the last measurement performed A display resembling Figure 5 4 appears showing the current result You can press W to view other previously stored results for this measurement or press Z to stop viewing the results 9 Press 3 to print the results of the last measurement performed ...

Страница 159: ...CSO measurement is done on a digital channel the average channel power is measured The Interactive mode and Automatic with Pause modes are used to perform the measurement This measurement is not available in the in service mode NOTE The CTB or CSO test result may be marked with an asterisk This indicates when a beat signal is within 2 dB of the 2715 s noise level Under these conditions the display...

Страница 160: ...ormal basis When earnestly measuring each CSO product on an in service basis the instrument moves to slightly below the selected beat frequency sets 30 kHz RBW and turns the video filter off The instrument begins gating the signal path so that the path is on only during quiet lines in the vertical interval It then internally acquires and averages a reasonable number of readings during gate on time...

Страница 161: ...arrier back on and proceeds to measure all the beats specified in the single sweep test table using the single sweep data Press CATV APPL to call up the CATV MEASUREMENTS menu See Figure 5 1 The Continuous mode is designed to run CSO tests repeatedly for 24 hours It assumes that the carrier of the channel under test has been turned off and will remain off for the duration of the test The Continuou...

Страница 162: ...ay shows the current time the time when the next cycle will start the time when the complete test will finish and the time the next normalization will occur The test may be stopped at any time by pushing the W or Z key When the test is stopped all results data acquired to that time is retained The results may only be viewed on an external computer The 2715 display shows how many beats were measure...

Страница 163: ...ldoff since it might be easier to visually detect beats in the analog mode 6 Turn the FREQ MKRS knob to place the first beat on a graticule line Make a note of this graticule line 7 Press CATV APPL 6 to enable the Digital display and move the marker to the graticule line noted in the preceding step 8 Press W to continue with the measurement At the end of the measurement the instrument displays the...

Страница 164: ...Z OFFSET 50 0DBC 750 000KHZ OFFSET 50 5DBC 0 00HZ OFFSET 50 5DBC 750 000KHZ OFFSET 50 5DBC 1 250MHZ OFFSET PRESS W TO CONT Z TO ABORT Figure 5 8 Typical CTB or CSO Measurement Results Display NOTE You can print measurement results only when the RS 232 interface is installed in the 2715 The GPIB interface does not support the print function Be sure to select handshaking UTIL 4 0 2 5 to match that e...

Страница 165: ...s the first second third fourth and fifth beats After the measurement is complete or after the routine is aborted the worst case result is displayed in the spectral display 10 Press CATV APPL to display the CTB or CSO menu 11 Press 1 to store the results of the last measurement After a short period of time the message RESULTS STORAGE COM PLETE is displayed 12 Press 2 to display results of the last...

Страница 166: ...the fifth beat frequency 7 Press 5 to use default frequencies 8 Press BKSP BKSP 0 to run the measurement The instrument measures the visual carrier peak for a reference then prompts you to turn off the carrier 9 Turn off the carrier and press W to continue or Z to abort the measure ment over the spectral display The instrument measures the beats within 100 kHz on either side of each frequency then...

Страница 167: ...ent points where beats are expected to occur relative to the visual carrier 2 Press 0 and enter the first beat frequency as an offset only from the visual carrier 3 Press 1 and enter the second beat frequency 4 Press 2 and enter the third beat frequency 5 Press 3 and enter the fourth beat frequency 6 Press 4 and enter the fifth beat frequency 7 Press 5 to use default frequencies 8 Press BKSP BKSP ...

Страница 168: ...d enter the third beat frequency 6 Press 3 and enter the fourth beat frequency 7 Press 4 and enter the fifth beat frequency 8 Press 5 to use default frequencies 9 Press 6 to specify the frequency of the carrier to be measured This is usually the next channel down in frequency 10 Press 7 to enter the test interval Minimum interval and default is 15 seconds The maximum test interval is 21600 seconds...

Страница 169: ...ults press W or to stop viewing press Z CSO STORED CHAN 71 09 AUG 93 12 00 00 STD 4 BEATS MEASURED 56 TIMES AT 15 SECOND INTERVALS 62 6DBMV MEASUREMENT FLOOR VIEW RESULTS VIA EXTERNAL PORT PRESS W TO CONT Z TO ABORT Figure 5 9 Typical Continuous Mode Results Display 17 Press 3 to print the results of the last measurement performed A printer must be connected to the 2715 NOTE You can print measurem...

Страница 170: ...conforms to the recommended NCTA procedure This method is often thought to most accurately reflect the level of visible picture impairment However this may not be the best method for measuring sideband amplitudes since cross modulation can also occur as phase modulation which the envelope detector used by this method does not detect Therefore the cross modulation sidebands can have significantly h...

Страница 171: ...extent that produces closest in sidebands 65 dB down from the carrier The Frequency Domain method would report a cross modulation level of 55 1 dBc but the Time Domain method would detect no cross modulation and would display CROSS MOD 48 DBC indicating that the cross modulation level was below its measurement limit If the cross modulation is the result of amplitude and phase effects the sidebands...

Страница 172: ... installed in the 2715 The GPIB interface does not support the print function Be sure to select handshaking UTIL 4 0 2 5 to match that expected by the printer or long jobs may not print completely 10 Press 4 to print the last stored results of the measurement A printer must be connected to the 2715 11 Press 9 to leave the Cross Modulation measurement and return to the CATV MEASUREMENTS menu In Cha...

Страница 173: ...de assists you in selecting a pair of measurement points The Automatic mode allows measurement levels at up to five locations that are entered using the IN CHAN RESP SETUP menu If you did not choose the in service basis you will be prompted to replace the modulated signal with a test signal for either interactive or automatic modes NOTE When doing the In Channel Response test in service and if the...

Страница 174: ...d 3 75 MHz all relative to the visual carrier NOTE Statutory proof of performance tests may require test frequencies other than the default values Frequencies entered into the 2715 s IN CHANNEL RESP SETUP menu items 2 through 7 must match the frequencies actually produced by your test generator If a sweep generator is used you may enter any frequency that is within the generator s range However do...

Страница 175: ...e an interactive in channel response measurement 1 Press CATV APPL to call up the CATV MEASUREMENTS menu See FigureĂ5 1 2 Press 9 7 to select the IN CHANNEL RESPONSE measurement menu This gives you the following options 0 RUN IN CHAN RESP 1 STORE CURRENT RESULTS 2 DISPLAY RESULTS 3 PRINT CURRENT RESULTS RS 232 Only 4 PRINT STORED RESULTS RS 232 Only 5 IN CHAN RESP SETUP 6 TEST SIGNAL LINE NUMBER 7...

Страница 176: ...SPONSE menu 10 Press 1 to store the results of the last measurement After a short period of time the message RESULTS STORAGE COM PLETE is displayed 11 Press 2 to display the results of the last measurement performed A display resembling Figure 5 8 on page 5 54 comes up At this point you can choose to either go ahead and view other previously stored results by pressing W or stop viewing the results...

Страница 177: ...cation 7 Press 7 and enter the sixth measurement location 8 Press BKSP 0 to run the measurement If measuring in service the instrument measures the visual carrier peak for a reference then enables gating on the specified TV line and measures the test signal amplitudes at the specified frequencies If measuring on the normal basis the instrument pauses and prompts you to switch to the appropriate fu...

Страница 178: ...LATION LINE 3 VIEW PICTURE 4 LISTEN These features are selected by pressing the number that applies to each and deselected by pressing the same number or pressing a number that applies to another feature This operation allows you to view a full field of baseband modulation in the analog mode This operation is not available for FM DATA and PILOT signals If this current channel has scrambling on as ...

Страница 179: ...2 The center frequency is set to the visual carrier frequency of the selected channel zero span is enabled the sweep rate is set to 10 µs division the resolution bandwidth is set to 5 MHz and the readouts are turned off If a VITS line is specified in the channel table you should see that VITS line If a VITS line is not specified then you should see line 17 of the video signal If you wish to change...

Страница 180: ... is TV the modulation type depends on the video polarity as described in Channel Tables on page 5 6 To listen to channel audio press CATV APPL 4 Use the outer LEVEL knob to set the audio level When the carrier has FM modulation the display shows the instantaneous FM deviation Top Screen 0 kHz Deflection Factor 10 kHz division The other bright trace waveform C accumulates the peak deviation in MIN ...

Страница 181: ...Spectrum Analyzer Menus ...

Страница 182: ......

Страница 183: ...d items from the sub menu may call up a secondary sub menu A few items from the menus are neither listed nor explained in the following discussions these represent factory troubleshooting and calibration aids not intended for general operator use Some items discussed may not appear in your instrument because of the installed options An overview of the menus is included in Operating Basics The over...

Страница 184: ...end of the line H If the 2715 accepts a smaller range of values it presents a secondary menu consisting of a list of the values that may be selected by pressing their corresponding keypad keys H If a parameter can have a wide range of numerical values two things happen First the selected item number is preceded by an asterisk to ensure there is no confusion about which item was selected Then you a...

Страница 185: ...c selection you press AUTO in the SWEEP function block on the front panel There are three ways to exit from a menu H Many selections cause the 2715 to revert automatically to the measurement mode it was in before calling up the menu In some cases a small delay is provided between making the selection and reverting to the spectral display to enable you to see the status indicator at the end of the ...

Страница 186: ...rator signal The spectral display appears and the word CALIBRATOR is now displayed at the lower right of the screen indicating the calibrator signal is on The calibrator signal is the peak at center screen Turning on the calibrator also internally disconnects the RF input path from the RF Attenuator and prevents viewing external signals 3 Press INPUT again The word following item 9 now is ON In th...

Страница 187: ...pt appears ENTER NEW VALUE OR W __ 0 TO 50 IN 2 DB STEPS W AUTO 10 Press 3 0 Y to enter a fixed value of 30 dB The display returns unchanged 11 Press b twice Now the signal peak and the noise floor both rise This is because pressing b twice increased the 2715 IF gain by 20 dB to lower the reference level but the RF attenuation is unchanged 12 Press INPUT 5 W to place the RF attenuation back in the...

Страница 188: ...relative to a µV m represents a simple change of scale Be aware that the 2715 always measures the voltage at its input across its 75 W input impedance and then scales the result according to the selected units Because the DBUV M is not just a simple unit conversion it is discussed separately in Using the DBUV M on page 6 10 When you want to measure a high amplitude signal it is possible that you w...

Страница 189: ... ratios relative amplitudes of signals close together in frequency interference levels relative to a nearby signal you can generally connect the 2715 directly to a 50 W source If a 50 W source is connected to the input of a 50 W instrument the voltage will be 1 6 dB lower than it is with the same source connected to the 75 W input of the 2715 We can also calculate that 0 dBmV dissipated in 75 W is...

Страница 190: ...equently used you can store the settings above in one of the STORED SETTINGS registers see the UTIL menu discussion on page 6 60 then you merely have to recall the settings each time a 50 W source is used with the 2715 Overdriving the 2715 s first mixer circuit can generate spurious signals and cause inaccurate measurements As the signal amplitude increases past the maximum linear range of the cir...

Страница 191: ... sensitivity using the preamplifier is 12 dB Above 600 MHz the preamplifier remains usable and useful but its flatness rolls off somewhat and is not specified To be effective the preamplifier must be used with no RF attenuation The preamplifier is not normally turned on because it can easily result in overdriving the first mixer The signal amplitude at the first mixer with the preamplifier on and ...

Страница 192: ...un can be included as part of your antenna The filter and external matching network are optional The filter is intended primarily to prevent off the air signals such as radio and television from swamping the 2715 The matching network may be necessary for maxi mum accuracy If in doubt try the measurement with and without the network If there is no difference omit the network for maximum sensitivity...

Страница 193: ...factor measurement distance and reference distance using the DBUV M SETUP under the REFERENCE LEVEL UNITS of the INPUT menu Note that many commercial antenna suppliers include the balun losses in the antenna factor For the most accurate results use an antenna calibrated at the specified reference distance and perform the measurement at that distance If possible measure the return loss of the anten...

Страница 194: ...appear The waveforms are repeatedly saved deleted saved and so on until you terminate the dBmV m mode At that point the last sweep is retained in the selected register Item 9 MARKER DISPLAY controls whether the on screen marker amplitude reads out in decibels relative to a microvolt per meter DBUV M or directly in volts per meter V m The reference unit does not change only the marker amplitude rea...

Страница 195: ... select the dBmV m unit while using these features Attempting to do so will result in an error message If you turn off the destination register while using dBmV m the message DBUV M MEASUREMENT MODE IDLE is displayed The dBmV m measurement is not made while idling and you still cannot unsave the destination register or use the LIN FM DEMODULATOR or EXTERNAL SOURCE features To disable the dBmV m me...

Страница 196: ...bort the procedure and store it Otherwise press W After the antenna is loaded its name if it has one or number is shown at the end of the first line of EDIT ANTENNA TABLE indicating that the antenna factors for that antenna have been loaded into the local buffer If you attempt to change the frequencies at which you plan to use an antenna whether it is a newly created antenna or an old one you must...

Страница 197: ...3 3 6 60 000000 3 5 10 If you are creating a new antenna table press Z to exit return to EDIT ANTENNA TABLE after the last entry has been completed If you are editing an existing table press W after your last entry Then press Z to return to EDIT ANTENNA TABLE Naming antennas is not required but names can provide quick reminders of the purpose of each antenna The following steps show how to name an...

Страница 198: ...TABLE 20 Choose the antenna data you want to print from the resulting list The DISPLAY LINE feature DSPL 8 can be used with the dBµV m for making vehicular surveys of leakage from cable TV installations or in other applications where an audible alert is useful whenever a signal amplitude crosses a preset threshold To sound a high level alert whenever the measured RF field strength exceeds the thre...

Страница 199: ... 3 Press 0 4 Press 1 7 5 X to specify a start frequency of 175 MHz Note that the indicated start frequency has changed 5 Press 1 6 Press 4 2 5 X to enter a value of 425 MHz for the stop frequency 7 Press any menu button to return to the spectral display The span is 25 MHz division making the start and stop frequencies 175 MHz and 425 MHz respectively If you make the start frequency greater than th...

Страница 200: ... that the resolution BW has also changed in response to the changed span div because RES BW was in AUTO mode 300 0MHz AUTO SWEEP ATTN 12DB 28 8DBMV VF WIDE 50 0MHz 10 DB 5MHz RBW AUTO CALIBRATOR Suppose you want to measure the difference in frequency between the peaks at 300 MHz and 500 MHz and between 500 MHz and 200 MHz The following steps show how to make these measurements 12 Enter marker mode...

Страница 201: ...Select item 0 from the Knob Function menu to change to frequency control 5 Press MKR FREQ The spectral display reappears 6 Rotate the FREQ MKRS knob several clicks clockwise Notice how the center frequency increases and the spectrum slides to the left One marker remains fixed on top of the cal signal peak while the other remains fixed at center scale Consequently the difference frequency also incr...

Страница 202: ...ou to conveniently flip between frequency and TV line control This can be very useful when viewing multiple TV channels You can select FREQUENCY for changing channels and then go to VIDEO LINE for choosing the line number For a complete explanation of TV LINE trigger mode see TV Line Trigger on page 6 85 300 0MHz AUTO SWEEP ATTN 10DB 28 8DBMV VF WIDE 50 0MHZ 10 DB 5MHZ RBW AUTO CALIBRATOR The fron...

Страница 203: ...ce level is changed to the signal amplitude to place signals at the reference level to make relative measurements It is also a convenient method of setting the video carrier to the reference level when using the video monitor option 10 When you are finished turn off the marker NOTE Signal amplitudes are always determined most accurately when the signal is within one division of the reference level...

Страница 204: ...n start frequency is selected the FREQ MKRS knob controls the frequency at the left edge of the display rather than the frequency at the center 4 Choose item 0 from the setup table The spectral display reappears but the center frequency bright spot is now moved to the left edge of the screen and the frequency readout is preceded by the letters SF as in SF 300MHz indicating that the start frequency...

Страница 205: ...er 11 Press MKR FREQ 0 Z to restore automatic threshold selection 12 Press any menu button to return to the spectral display The 2715 enables you to change the resolution of its built in counter It is possible to specify its resolution as 1 kHz or 1 Hz or to turn off the counter when the Signal Track mode is in use Be aware that this feature only changes the counter resolution to 1 Hz not the accu...

Страница 206: ...n the FREQ MKRS knob one click clockwise The frequency is changed 300 MHz 4 Reset the center frequency to 300 MHz 5 Turn on the marker 6 Position the marker at 150 MHz 7 Select item 1 from the MKR FREQ menu 8 Now choose item 1 currently MARKER FREQ from the Programmed Tuning Increment menu to select the marker frequency as the tuning increment 9 Turn off the marker and turn the FREQ MKRS knob one ...

Страница 207: ...tral display reappears 18 Turn the FREQ MKRS knob The frequency changes by 7 MHz per click a value not otherwise available Entering a keypad tuning increment automatically places the 2715 in programmed tuning mode 19 There are two ways to turn off any programmed increment including the keypad entered increment a First toggle item 8 on the Marker Frequency menu to read AUTO This turns off the keypa...

Страница 208: ...ut of a down converter with a 5 15 GHz local oscillator perform the following steps 1 Press MKR FREQ to call up the Marker Frequency menu 2 Press 9 to select SETUP TABLE 3 Press 3 to select FREQ OFFSET 4 Enter an offset of 5 15 GHz ignore the CALIBRATOR DOESN T MATCH READOUT warning Notice that the status of item 4 FREQ OFFSET MODE changed from OFF to ON PLUS 5 Press 4 several times The status of ...

Страница 209: ...e other hand have local oscillator frequencies below the input signal frequency and you use ON PLUS when viewing their output signals DSPL 300 0MHz AUTO SWEEP ATTN 12DB 8 8DBMV VF WIDE 20 0MHz 10 DB 5MHz RBW AUTO CALIBRATOR The Display menu enables you to change the appearance of the display screen and the signals presented on it From the Display menu you can do the following H Switch between anal...

Страница 210: ...again Both the saved C digital display and the current D digital display return the same register configuration that was in use prior to entering the analog mode by selecting item 0 16 Turn on the B register and then turn off all registers in the order D C B 17 Press DSPL 0 Notice that the B register the last one turned off is the only one reactivated 18 Reset the center frequency to 300 MHz and t...

Страница 211: ... C but you cannot store the average in a register that already contains data Register D is not available because it always contains the current trace If you plan to use the stored average as a reference and perhaps intend to subtract it from other spectra you must store it in register A Whichever register is used it must be cleared before you attempt to store new data in it or you will receive an ...

Страница 212: ...ter is the only one turned on 25 Turn the D register on and off several times and note the difference Most of the sweep to sweep variations in the noise have disappeared Now we will repeat the experiment this time storing the MAX average in register B In this case only the 256 maximum values of each max min sweep are averaged and stored 26 Press DSPL 1 3 to select MAX 27 Press 8 repeatedly to sele...

Страница 213: ...visual mean and average maximum and minimum values superimposed The mean along with the max and min values provide an estimate of the variability of the signal The signal peak does not appear to have changed because the calibration signal is essentially constant little or no variability so its min max and mean amplitude are all about the same This can be used to advantage 37 Turn off the A B and C...

Страница 214: ...m 3 once 4 Press DSPL 2 to activate the B C MINUS A mode 5 Turn on the B register and turn off A and D The display now consists of a much reduced and totally flat noise floor and some intermittent peaks similar to Figure 6 5 The zero frequency and calibration signal peaks have almost disappeared You have subtracted the average max min spectrum stored in the A register from the active sweep in the ...

Страница 215: ...he reference level 10 dB The calibration signal peaks appear 7 Increase the reference level 20 dB The technique works no matter the direction of the signal change 8 Reset the reference level to 18 8 dBmV and change the center frequency slightly Again the calibration signal peaks appear Any change from the average either amplitude or frequency becomes obvious ...

Страница 216: ...f the noise in register A you need to overwrite the display currently stored in register A 12 After the average is complete turn the calibrator back on and activate MAX HOLD in register B The resulting traces are shown in Figure 6 6 MAX HOLD plus noise Average MEAN noise Figure 6 6 Average MEAN Noise and MAX HOLD Signal Plus Noise 13 Turn off the A register 14 Press DSPL 2 to enter the B C MINUS A...

Страница 217: ...ee Figure 6 8 The points labeled A and B in Figures 6 7 and 6 8 have exactly the same value in each figure Imagine that the screen curves backwards at the top and bottom until it joins itself forming a cylinder All points of zero difference lie along the joint Now cut the joint and uncurl the cylinder allowing it to become a flat screen again Both the top and bottom of the screen represent zero di...

Страница 218: ...ximum amplitude only is sampled and displayed at all 512 points The Max Min mode has the advantage of bearing some semblance to the analog signal and readily revealing pulsed versus constant carrier signals Pulsed signals cause the signal peaks to be filled in 3 Leave the display in the MAX MIN mode 175 0MHz AUTO SWEEP ATTN 2DB 18 8DBMV VF WIDE 20 0MHz 10 DB 5MHz RBW AUTO CALIBRATOR If you want to...

Страница 219: ...douts move down one row to accommodate the title even if the title field is blank Select item 2 to edit an existing title or to enter a new title If the display is already titled the title appears in the upper left with an underscore cursor beneath the first letter If the display is untitled just the cursor appears The characters that can be used in the title are listed below the title in three li...

Страница 220: ...veform Perma nently attach it to a waveform C 12 Press SAVE ENABLE and C 13 Press DSPL 5 2 Y to delete the title from the display title buffer 14 Return to the spectral display The title is gone but the readouts are displaced downward one line because TITLE MODE is still enabled 15 Turn off the D register and turn on C The title is back it has become part of the saved waveform in C The title will ...

Страница 221: ...aveform 18 Move the cursor one division to the right of center screen and two divisions down from the reference level 19 Enter the characters 2ND HARMONIC 20 Move the cursor to the peak at the left of the screen label it FUNDAMEN TAL The labels denote the calibrator signal and its second harmonic 21 Press X to store the label s Pressing Z exits from the procedure without any changes 22 Press 3 fro...

Страница 222: ...15 on pin 1 of the rear panel Accessory Connector J103 and must be in the range of 0 to 1 4 V with a 3 dB bandwidth of 50 kHz or less DISPLAY STORAGE VERT SCALE 10 5 1 SWEEP RATE and some VID FLTR selections 10 Hz 1 kHz 10 kHz 100 kHz remain active and can be used to process the external signal Refer to J103 Accessory Connector on page E 2 in Appendix E External Input and Output for additional det...

Страница 223: ... item 3 is selected you receive an error message 7 Press DSPL 8 8 Press 4 to select LIMIT DETECTOR The end of line status indicator changes to OVER the display line has been made an upper limit If an on screen signal goes over the limit the audio alarm sounds 9 Press DSPL to return to the spectral display The alarm should be sounding When the limit detector and the display line are both selected t...

Страница 224: ...ector feature converts the user definable command WAIT FOR END OF SWEEP to a WAIT FOR LIMIT command see USER DEF on page 6 89 This is a handy way to halt the execution of a user defined routine until the alarm condition has been satisfied If you change the reference level while using the display line limit detector feature the line changes position on screen to track the new reference level Press ...

Страница 225: ...mplitude in register B With the A B and D registers displayed you have an upper and lower bound on the real time signal in D As time passes you will notice that the upper and lower bounds no longer change because the probability of new random spectral peaks exceeding those already observed becomes very small 4 Press DSPL 9 to turn off the minimum hold feature Reselecting MIN HOLD when it is alread...

Страница 226: ...he 2715 measures signal bandwidth by detecting the signal peak and then finding the frequency points on the signal spectrum that are a designated number of dB down from the peak You specify the number of dB using the Application menu Setup Table The difference between the frequency points is the bandwidth Optimum resolution is obtained by spreading the signal across as large a portion of the scree...

Страница 227: ...will vary slightly about 300 kHz 8 Press b next to SPAN DIV until the span readout is 10 0KHZ 9 Press RES BW b until RBW readout is 30KHZ The bandwidth should now read approximately 30 kHz The 2715 remains in bandwidth mode until you call up the Applications menu and toggle it off make an alternate selection or until you turn off the markers 10 Press APPL 0 to turn off bandwidth mode 100 0MHz AUTO...

Страница 228: ...the spectral display This is because the 2715 does not compute the arithmetic mean of the minimum and maximum values using decibels that yields an incorrect answer The display does not change but you may notice a pause while the 2715 carries out the noise measuring algorithm First the 2715 measures the average noise power in ZERO SPAN using a narrow bandwidth video filter see a better approximatio...

Страница 229: ...ght on screen column read approximately as follows C N 63 0DB 5 0MHZ The reading may vary slightly You will also receive the NOISE LEVEL LESS THAN 2DB warning The C N reading is the ratio of the signal power at the fixed marker s position to the average noise power at the movable marker position The noise reading is corrected as indicated in the normalized noise measurement section Since the noise...

Страница 230: ...e to measure both noise and C N on our hypothetical cable 26 Turn off the preamp and noise measurement mode 27 Press UTIL 1 1 to reinitialize the 2715 to the factory default power up settings NOTE If the 2715 is in the PEAK acquisition mode it reverts to MAX MIN mode whenever the normalized noise or carrier to noise features are activated You can return it to PEAK mode by pressing DSPL 4 900 0MHz ...

Страница 231: ...e fend fbegin Last Search Range Total Search Range 1st Search Range 2nd Search Range Last 1 Search Range 10xSPAN DIV 10xSPAN DIV 10xSPAN DIV 10xSPAN DIV Figure 6 10 The SIGNAL SEARCH Frequency Range To see how SIGNAL SEARCH works reset the following 2715 controls to search the frequency range from 55 to 550 MHz SPAN DIV 5 0MHz RESOLUTION BW 300 0KHz REFERENCE LEVEL 28 8DBMV VIDEO FILTER 300 0KHz 1...

Страница 232: ...ment parameters 10 Press UTIL 4 2 to select PRINTER CONFIGURATION from the SYSTEM CONFIGURATION menu 11 Press 0 until the status indicator reads CRT this feature is explained in the UTIL discussion on page 6 60 12 Press UTIL 13 Press CATV APPL 3 to reselect the SIGNAL SEARCH MENU from the Application menu Notice that the number of signals detected is displayed at the end of item 3 DISPLAY RESULTS ...

Страница 233: ...ve and below the signal beyond which half the power not in the occupied bandwidth resides The frequency difference between the upper and lower cells is the n occupied bandwidth For instance if you specify the 90 occupied bandwidth the 2715 first computes the total signal power Next it sums the signal power in the cells starting at the left hand edge until it accumulates 5 of the total The percent ...

Страница 234: ... 2 Ensure that the calibrator is turned off 3 Adjust the reference level until you can see individual FM broadcast or TV sound carrier signal peaks 4 Tune the 2715 until a strong signal is centered Your display might resemble Figure 6 12 100 38MHZ 18 8DBMV 1 0MHZ 300KHZ RBW ATTN 10DB VF 300KHZ 10 DB FREQ Figure 6 12 Portion of U S Broadcast FM Band 5 Press CATV APPL to return to the Applications m...

Страница 235: ...ÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ ÌÌÌÌÌÌÌÌÌÌÌÌÌÌÌ 100 38MHZ 18 8DBMV 50 0KHZ 300KHZ RBW ATTN 10DB VF 300KHZ 10 DB FREQ Markers Denote Occupied Bandwidth Figure 6 13 OCCUPIED BW Mode with MAX HOLD To obtain best frequency accuracy when making occupied BW measurements as with signal bandwidth measurements use small spans division spread the signal over as much of the screen as possible subject to the following li...

Страница 236: ...spectral display of signal power vs frequency However by selecting FM DEVIATION MODE you can view instantaneous frequency variations vs time 1 Connect a short antenna or CATV tap to the 2715 input as outlined in Appendix B Broadcast AM FM and TV Signal Sources 2 Ensure that the calibrator is turned off 3 Adjust the reference level until you can see individual FM broadcast or TV sound carrier signa...

Страница 237: ...ycle through the frequency deviation scales set the vertical scale to 10 kHz div 8 Press DSPL 9 W to select MIN HOLD IN WFM A Let the data accumulate for two to three minutes A ragged horizontal waveform develops indicating the maximum frequency excursions during the observation period Maximum Deviation Instantaneous Deviation Figure 6 14 Instantaneous Frequency Deviation and Maximum Observed Devi...

Страница 238: ...hould be used see Tektronix application note 26W 7037 1 Spectrum Analyzer Fundamentals DEMOD 100 0MHz AUTO SWEEP ATTN 0DB 18 8DBMV VF 300KHz 1 0MHz 10 DB 300KHz RBW AUTO The DEMOD menu provides a means of listening to AM or FM modulation on the signals being analyzed and activating the video monitor mode Listening to signals often helps to identify the source A built in speaker is provided but if ...

Страница 239: ...ectral display To listen to AM transmissions connect an antenna to the 2715 as outlined in Appendix B Broadcast AM FM and TV Signal Sources The antenna will probably need to be much longer than for FM 12 Press CHAN FREQ 1 X to set the center frequency to 1 MHz 13 Press SPAN DIV 1 0 Y to set span to 10 kHz div 14 Ensure RES BW and SWEEP are set to AUTO 15 Ensure that the calibrator is turned off 16...

Страница 240: ...ifying signals and determining the nature of interference 1 Press DEMOD to call up the DEMOD TG menu Item 3 is an on off toggle that may indicate BROADCAST AM VIDEO or SATELLITE FM VIDEO depending on the mode that was last selected The BROADCAST mode is used for off air or cable TV signals SATELLITE is used for example when viewing FM video signals at the output of a block down converter LNB In th...

Страница 241: ...line The signal level is very important for proper performance3 and must also be well above the noise floor 10 Press DEMOD 3 to select BROADCAST AM VIDEO When item 3 is activated the 2715 presets a number of measurement parameters in order to generate a TV picture You may be able to obtain a slightly better picture by changing some settings 11 Experiment with the following controls H REF LEVEL use...

Страница 242: ...f time how the 2715 is to be configured The following example uses the Utility menu to reset the center frequency reference level and span You could also set the resolution BW video filter vertical scale and sweep rate 1 Press INPUT 9 to turn on the calibrator 2 Press UTIL 2 to select the KEYPAD ENTERED SETTINGS from the Utility menu This item enables you to set instrument controls to specific val...

Страница 243: ...ethod of manually setting the video filter bandwidth The video filter bandwidth can be set to AUTO in which case it is 1 100 of the resolution bandwidth in normal mode or fixed from 3 Hz to 300 kHz in a 1 3 sequence 3 Hz 10 Hz 100 kHz 300 kHz other values will be converted to the nearest allowable values H Selecting item 6 VERTICAL SCALE calls up another menu that enables you to select any of the ...

Страница 244: ...C that are not currently saved but currently saved registers will not be overwrit ten To recall a previously saved display first unsave its destination register The following example demonstrates the ability the 2715 has to recall the last settings in effect before the power was turned off 14 Turn off the 2715 and then turn it on again 15 Press UTIL call up the Utility menu 16 Press 1 to select ST...

Страница 245: ... disappear following warmup as soon as you use a control The remaining items on the Stored Settings Displays menu can be used exactly as you used USER DEFINED POWER UP SETTINGS The difference is that they are not automatically implemented at power up time or by the initialization selection they must be recalled from the Stored Settings Displays menu 6 Press INPUT 9 to turn on the calibrator 7 Pres...

Страница 246: ...o reinitialize the 2715 to your user defined power up settings 25 Press UTIL 1 Item 3 reads as follows AB 90MHZ 38 8DBMV 20MHZ This message shows the primary control settings that are saved in that location and tells you register A and B waveforms are saved along with the settings 26 Press 3 W The control settings and the saved waveforms are both restored Whenever you save settings including LAST ...

Страница 247: ...M Using external signals to achieve even greater measurement accuracy or to renormalize the reference if NVRAM should ever be lost is described later in Service Normalizations on page 6 80 If the 2715 self test routine detects that the present 2715 gain or frequency characteristics differ significantly from those determined during the previous normalization the NORMALIZATION SUGGESTED message is d...

Страница 248: ...r frequency normalization and several minutes for both Routinely select ALL PARAMETERS to ensure the 2715 measures amplitude and frequency as accurately as possible but if you are in a hurry you can select only the parame ters that are most important to your measurements 3 Disconnect all signals from the 2715 input 4 Press 0 to select ALL PARAMETERS Typically you will see a number of changing wave...

Страница 249: ...le The RS 232 port is modem compatible and makes possible remote operation via a telephone line Port connectors are located on the rear panel See Appendix E External Input and Output The accompanying Programmer Manual contains additional information about setting up and configuring the 2715 for remote or automated operations and complete explanations of the commands that are used See the Programme...

Страница 250: ...f data bits per word The default is 8 bits and is required for binary data transfers Seven bits can be used for ASCII character transfers H Item 3 PARITY cycles between NONE ODD and EVEN The default is NONE H Item 4 EOL sets the end of message designator when a message is sent by the 2715 When a message is transmitted over RS 232 the instrument sending the message signifies that the message has be...

Страница 251: ...nfiguration menu appears Several choices are offered in all cases the 2715 settings must match those used by the controller or printer plotter H Item 0 STATUS enables you to toggle the GPIB port on and off line The port must be on line to communicate with any other device H Item 1 GPIB ADDRESS specifies the primary address the 2715 does not support secondary addresses that can be any value from 0 ...

Страница 252: ... disconnect all instru ments except the 2715 and the plotter from the bus Place the plotter in the listen only mode usually done with controls on the plotter You can then send screen data from the 2715 to the plotter by pressing PLOT Whichever communications port is installed in your 2715 the spectral display and its attendant information can be sent to a printer or plotter by pressing PLOT but yo...

Страница 253: ... measurements enable you to send ASCII character strings to the CRT or to the optional RS 232 port if it is installed You cannot send these strings to a GPIB device 1 Press UTIL 4 to return to the SYSTEM CONFIGURATION menu 2 Press 2 to select PRINTER CONFIGURATION 3 Press 0 to select PRINTER DEVICE The PRINTER DEVICE will toggle between TTY00 and CRT TTY00 is functional only if an RS 232 interface...

Страница 254: ...of item 1 3 Experiment if you want then restore the factory default value NOTE This feature is used primarily for certain procedures at the factory we recommend that you leave WAVEFORM TO PRINTER turned off Item 2 of the INSTRUMENT CONFIGURATION menu WAVEFORM TO PRINTER UTIL 4 3 2 sends a binary or ASCII representation of the displayed waveform to the serial port following each sweep The 2715 must...

Страница 255: ...them to the displayed trace It does this between sweeps You can shorten the intersweep interval by disabling the frequency corrections although some high frequency accuracy may be sacrificed and the signal may drift off screen at small spans div NOTE Short Holdoff mode reduces the intersweep interval even further but also disables most marker measurement modes 1 Observe the spectral display for a ...

Страница 256: ...bilize For faster response time when continuous observation of signals is necessary the delay can be minimized by entering the short holdoff mode When using short holdoff in the AUTO sweep mode a fictitious signal sometimes appears at the left edge of the screen NOTE Turning on SHORT HOLDOFF disables frequency corrections and most marker measurement modes 11 Ensure the spectral display is turned o...

Страница 257: ... to return to the UTILITY menu 4 Press 1 to select STORED SETTINGS DISPLAYS 5 Attempt to delete any stored setting The message ONLY WAVEFORMS DELETED appears When STORED SETTINGS PROTECT is turned on you cannot delete the stored settings but waveforms stored along with them will be deleted 6 Press BKSP 4 to return to the SYSTEM CONFIGURATION menu 7 Press 5 to turn off STORED SETTINGS PROTECT 8 Pre...

Страница 258: ...ent results in a designated location 1 4 RSLT3 saves the CATV measurement results in the number 3 location Flatness Correction Data Files Flatness files save the data generated by running the flatness correction procedure Antenna Table Files Each file saves the antenna table in a designated location 1 5 representing antenna data for a particular antenna ACF3 saves the antenna information in locati...

Страница 259: ...It is now impossible to delete the file without first unprotecting it Repeat the foregoing process to unprotect a previously protected file The process constitutes a toggle that alternately protects and unprotects the desig nated file NOTE Unless you have specific reasons for doing otherwise do not protect system parameter and normalization files see Table 5 6 on page 5 15 Doing so may prevent the...

Страница 260: ...HORIZ POS control until the vertical center line of the display coincides with the center vertical line of the graticule 8 After completing the alignment repeatedly press UTIL until the spectral display reappears You may improve the center frequency setting time in some applications by changing the YIG oscillator settling delay time from the factory default value The factory YIG oscillator settlin...

Страница 261: ...creased or returned to 5000 ms If the YIG oscillator settling time is changed from the factory default a message indicating this case is displayed during instrument power up This is a reminder to you that the factory default value is no longer being used Instruments returned to Tektronix for repair and or calibration will have the YIG oscillator settling time returned to the factory default value ...

Страница 262: ...ference values for the on board calibration signal and attenuator with respect to more precisely known alternate sources The alternate sources must exceed the following specifications frequency 5 parts in 107 10 Hz amplitude 18 8 0 1 dBmV 100 1 MHz attenuation gain step 10 0 5 dB 100 1 MHz We will not give examples for all reference normalizations but we will show you how to determine a new freque...

Страница 263: ...mpatible printer on line a plotter will not work unless it can emulate an FX series printer with the paper in the correct position 11 Select item 5 from the Service Normalizations menu Printing starts immediately Control of the 2715 is returned following printout NOTE If NVRAM is lost the flatness correction data will also be lost This data can be reloaded by a Tektronix service center or by using...

Страница 264: ...ormalize the 2715 each time it is used until the battery can be replaced NOTE Any control settings can be used Utility menu item 6 SERVICE REQUEST enables you to manually generate a service request SRQ whenever required for testing or other purposes See the 2714 2715 Programmer Manual for detailed information about SRQs and their uses To generate a SRQ press UTIL 6 If the communications port is on...

Страница 265: ...e sweep generator is free running A new sweep begins as soon as possible after the end of the previous sweep However when dealing with time domain analysis or pulsed signals it may be advantageous to trigger the sweep from some characteristic of the input signal or from another signal related in a fixed way to the input signal The Sweep Trigger menu also enables you to specify the sweep rate and e...

Страница 266: ...the spectral display The LEVEL control adjusts a threshold so that the sweep begins when the amplitude of the input signal crosses that threshold 1 Connect a short antenna or CATV tap to the 2715 input as outlined in Appendix B Broadcast AM FM and TV Signal Sources 2 Tune to a strong television video carrier and adjust the signal height to near the reference level 3 Set the 2715 to LIN mode zero s...

Страница 267: ...e display may be slowly drifting or stationary TV sweep rates are nearly harmonically related to line frequency but small fractional hertz differences create the slow drift 11 Turn on the readouts 100 0MHz AUTO SWEEP ATTN 12DB 28 8DBMV VF 300KHz 1 0MHz 10 DB 300KHz RBW AUTO Item 4 TV LINE of the Sweep Trigger menu is one of two internal triggering modes that are particularly useful for time domain...

Страница 268: ...tral display 7 Turn off digital storage and select zero span 8 Enter LIN mode and change the sweep rate to 20 msec div sweep rate is indicated in the left hand readout column The screen should resemble Figure 6 16 In CONTINUOUS mode the sweep generator is triggered by the first pulse that occurs after the 2715 enters the ready to be triggered state In other words after the 2715 completes the curre...

Страница 269: ...it 11 Turn to about line 17 to view several lines including the vertical interval test signal VITS This signal is usually present between lines 15 20 in the U S see Figure 6 17 The display is not as bright as it was in the CONTINUOUS mode because the 2715 is triggering on and displaying only one horizontal line out of every 525 If the display is too dim adjust the INTENSITY control Figure 6 17 Vid...

Страница 270: ... the Sweep Trigger menu and choose item 5 The display is now being triggered by the TV vertical sync pulse that occurs near the beginning of each field Using the SWEEP arrow keys slow the sweep rate to 2 ms div The display resembles Figure 6 15 on page 6 84 You can now see an entire frame of video information with the start of the frame at the left of the display The frame does not slip sideways a...

Страница 271: ... while listening to demodulated signals the 2715 acts like a radio receiver The operator can stop at any station since the sweep is being manually controlled 5 Toggle the manual scan mode off by selecting item 7 again USER DEF 100 0MHz AUTO SWEEP ATTN 12DB 28 8DBMV VF WIDE 20MHz 10 DB 5MHz RBW AUTO The User Definable menu enables you to store and execute user definable sequences of keystrokes call...

Страница 272: ...ection The title can be up to 28 characters long Remember to press X to store the title Titling the routine is not mandatory if you do not supply a title the routine is named PROGRAM by default but does help you to recall what a routine is supposed to do 2 Select item 0 ACQUIRE EXIT KEYSTROKES from the USER DEF PROG UTILITIES This begins the accumulation of keystrokes The spectral display reappear...

Страница 273: ...rst delete the prior routine 12 To prevent your routine from accidental erasure press USER DEF 9 and select item 8 PROTECT and then press 3 Select item 7 DELETE and notice the next to your routine indicating that it is protected Press 3 W The following message appears REMOVE PROTECTION FIRST To remove the protection press BKSP 8 3 You can now delete the routine if you wish 13 To execute the UDP pr...

Страница 274: ...Spectrum Analyzer Menus 6 92 2715 User Manual ...

Страница 275: ...Appendices ...

Страница 276: ......

Страница 277: ...15 minute warm up period within the environmental limits and after all normalization procedures have been carried out Information in the Performance Requirement column of Tables A 2 through A 8 is guaranteed and verifiable unless otherwise noted Supplemental Information is intended to further explain a characteristic its performance requirement or to describe characteristic performance that is imp...

Страница 278: ...ier Frequency Measurement Aural carrier measured relative to the visual carrier Method Internal Counter Difference Range 1 MHz to 10 MHz3 for an amplitude difference of 30 dB and aural C N 15 dB 300 kHz RBW Resolution 1 Hz Accuracy 15 Hz for visual to aural carrier difference 8 MHz Visual Carrier Peak Level Measurement Absolute peak amplitude of visual carrier measured with PREAMP OFF Accurate Fre...

Страница 279: ...sync tip to lowest white level found in 10 sweeps the VITS line is used if it is defined in the channel table AM Range 50 to 95 Resolution 0 1 Accuracy 2 for visual C N 40 dB 300 kHz RBW HUM LFD Measurement Typical Power line frequency is measured on an unmodulated visual carrier and low frequency disturbance LFD is measured on the modulated carrier AM Range 1 to 10 peak to peak Resolution 0 1 Acc...

Страница 280: ...r peak according to the NCTA recommended spectrum analyzer settings SINGLE SWEEP and CONTINUOUS modes do not use all the NCTA recommended settings Optimum Input Range See Figure A 3 on page A 8 Maximum Range See Figure A 3 on page A 8 Resolution 0 3 dB Accuracy See Figure A 3 on page A 8 In Service CSO Typical CSO products are measured per NCTA recommendations during quiet lines in the vertical in...

Страница 281: ...300 kHz RBW Frequency Range 15 MHz to 1015 MHz Resolution 0 3 dB Absolute Accuracy 2 7 dB for visual C N 30 dB 300 kHz RBW and for FM signal C N 33 dB 100 kHz RBW assumes flatness corrections are present Relative Accuracy 0 8 dB relative to adjacent channel 1 5 dB relative to all other channels Aural Carrier Difference Range 0 to 30 dB for C N 15 dB 300 kHz RBW Resolution 0 3 dB Accuracy 1 1 dB fo...

Страница 282: ...ation function Line Format NTSC or PAL Line Range 1 to 525 NTSC 1 to 625 PAL Sweep Time 10 s div In Channel Response Range 3 dB the auto test is run in 1 dB div Resolution 0 1 dB Accuracy 0 5 dB Auto mode 0 8 dB Interactive mode Adjacent Channel Leakage Typical Averaged power in adjacent channel s is divided by averaged power for the test channel Resolution 0 1 dB Accuracy 2 0 dB within limits sho...

Страница 283: ...asurement 4 dB to 500 MHz Note 1 2 dB to 500 MHz Note 1 4 dB to 500 MHz Note 2 2 dB to 500 MHz Note 2 4 dB at 1000 MHz Note 2 2 dB at 1000 MHz Note 2 CTB Measurement Limit dBc 0 10 20 30 40 50 60 70 80 90 30 20 10 0 10 20 30 40 50 60 70 Note 1 Approximate extended limits if preselector is used and mixer input level is set to 20 dBm Note 2 Normal limits without preselector and mixer input level set...

Страница 284: ...Hz Minimum signal level for gated measurement to 500 MHz Figure A 3 Typical Accuracy Limits for Nongated CSO Measurement 4 dB to 500 MHz Note 1 2 dB to 500 MHz Note 1 4 dB to 500 MHz Note 2 2 dB to 500 MHz Note 2 4 dB at 1000 MHz Note 2 2 dB at 1000 MHz Note 2 CSO Measurement Limit dBc 0 10 20 30 40 50 60 70 80 90 30 20 10 0 10 20 30 40 50 60 70 Note 1 Approximate extended limits if preselector is...

Страница 285: ...B 25 35 45 55 65 20 10 0 10 20 30 40 50 60 70 CHANNEL UNDER TEST INPUT LEVEL dBmV To 500 MHz using preselector 500 MHz to 1000 MHz using preselector To 500 MHz in 60 channel flat system dominated by analog signals 10 dB stronger than average power of channel under test 500 MHz to 1000 MHz in 60 channel flat system dominated by analog signals 10 dB stronger than average power of channel under test ...

Страница 286: ...han average power of channel under test Figure A 7 Typical Digital Signal CSO Measurement Range Limit for 2 dB Accuracy Measurement Limit dBc 25 35 45 55 65 20 10 0 10 20 30 40 50 60 70 INPUT LEVEL dBmV To 500 MHz using preselector 500 MHz to 1000 MHz using preselector To 500 MHz in 60 channel flat system dominated by analog signals 10 dB stronger than average power of channel under test 500 MHz t...

Страница 287: ...Option 50 and Option 75 400 Hz up to 1 8 GHz Option 50 and Option 75 500 Hz above 1 8 GHz With frequency corrections enabled Readout Resolution 1 kHz or 1 Hz counter readout menu selectable Frequency Span Div Range Using SPAN DIV y and SPAN DIV b buttons selections in a 1 2 5 sequence Using the keypad or UTIL menu select any value from 100 MHz div to 1 kHz div In MAXSPAN 180 MHz div All except Opt...

Страница 288: ...d Option 75 2 4 KHz peak to peak total excursion in 20 ms above 1 8 GHz Resolution Bandwidth 6 dB down Resolution bandwidth selections are 5 MHz 1 MHz 300 kHz 100 kHz 30 kHz 10 kHz 3 kHz 1 kHz and 300 Hz for the spectrum analyzer Shape Factor 60 dB 6 dB 7 1 or less for all resolution bandwidths 1 MHz Noise Sidebands All except Option 50 and Option 75 70 dBc at 30X Resolution Bandwidth for all reso...

Страница 289: ...de Related Characteristics Characteristic Performance Requirement Supplemental Information Marker The frequency and amplitude values of the marker position are displayed and are preceded by the letter M MKR and MKR a position the marker to the next right or left signal peak respectively Accuracy Frequency Same as SPAN DIV Amplitude A function of the reference level vertical scale factor and normal...

Страница 290: ...r than the threshold level If the strength of a signal being tracked decreases below the threshold level the instrument displays the message NO SIGNAL FOUND ABOVE THRESHOLD Table A 4 Amplitude Related Characteristics Characteristic Performance Requirement Supplemental Information Vertical Display Mode 10 dB div 5 dB div 1 dB div and Linear Reference Level Range Top of graticule Log Mode 21 2 dBmV ...

Страница 291: ...l level applied near frequency of 2 11 GHz Display Dynamic Range is reduced if there is signal energy at or near 2 11 GHz Accuracy 10 dB div Mode 1 0 dB 10 dB to a maximum cumulative error of 2 0 dB over the 70 dB range and a maximum cumulative error of 4 0 dB over the 80 dB range 10 dB div accuracy and range is affected by the signal to noise ratio of the selected Resolution Bandwidth filter See ...

Страница 292: ...mV 45 dBmV 43 dBmV 102 dBm 94 dBm 92 dBm linearly approximately 10 dB NOTE Sensitivity degrades as the R 30 kHz 58 dBmV 50 dBmV 48 dBmV 107 dBm 99 dBm 97 dBm FREQUENCY setting is decreased from approximately 10 MHz to 9 kHz 10 kHz 63 dBmV 55 dBmV 53 dBmV 112 dBm 104 dBm 102 dBm Maximum loss in sensitivity is approxi mately 20 dB 3 kHz 68 dBmV 60 dBmV 58 dBmV 117 dBm 109 dBm 107 dBm 1 kHz 73 dBmV 6...

Страница 293: ...ut level of 9 dBmV LO Local Oscillator Emission All except Option 50 and Option 75 21 dBmV 70 dBm With 0 dB RF attenuation and preamp off Option 50 and Option 75 When frequency is below 90 MHz Typically 29 dBmV 20 dBm When frequency is above 350 MHz Typically 21 dBmV 70 dBm Table A 5 Input Output Signal Characteristics Characteristic Performance Requirement Supplemental Information RF Input Type F...

Страница 294: ...gic high level while the CRT beam is sweeping Pin 3 Chassis and Signal Ground Pin 4 Sweep Output 1 3 V 1 3 V Provides a nominal 1 3 V to 1 3 V negative going ramp proportional to the horizontal sweep output impedance 50 W Pin 5 Log Video Output Provides 0 V to 1 6 V of video signal inversely proportional to the vertical display amplitude 0 V is the top of the screen Impedance is 1 kW Pin 6 CLK0 Ou...

Страница 295: ...mental Information Input Voltage Line Voltage Range 90 VAC to 250 VAC Line Frequency Range 48 Hz to 63 Hz Line Voltage Range 90 VAC to 132 VAC Line Frequency Range 48 Hz to 440 Hz Line Fuse 2 A Slow Blow Input Power 90 W 1 2 A for standard instrument 105 W 1 4 A maximum with options 115 W maximum at 90 V and 440 Hz At 115 V and 60 Hz Leakage Current 3 5 mARMS maximum or 5 mApeak maximum Table A 7 ...

Страница 296: ...al Trigger Level See EXT TRIG in Table A 5 Nonvolatile Memory Battery Backed Up Instrument settings waveforms and normalization results are stored in NVRAM Battery Life Lithium At 55_ C Ambient Temperature 1 to 2 years At 25_ C Ambient Temperature At least 5 years Temperature Range for Retaining Data 10_ C to 75_ C Internal Calibrator Provides 100 MHz marker for amplitude calibration and comb of 1...

Страница 297: ...27 MHz 500 MHz IEC 801 3 Performance Requirement No responses above 90 dBm in a 3 V meter field Fast Transients Capacitive Clamp 1 kV Power Leads 500 V Control Leads IEC 801 4 Power Line Surge 1 kV Differential Mode 2 kV common mode IEC 801 5 Temperature Operating 0_ C to 50_ C Nonoperating1 55_ C to 75_ C2 Humidity Operating 95 RH 5 30_ C and below 75 RH 5 31_ C through 40_ C 45 RH 5 41_ C throug...

Страница 298: ...ng and Nonoperating Three guillotine type shocks of 30 g one half sine 11 ms duration each direction along each major axis total of 18 shocks no drops allowed on the front surface and front corners Transit Drop Free Fall 8 in 203 2 mm one per each of 5 faces and 4 corners instrument is tested and meets drop height of 12 in 304 8 mm Table A 10 Physical Characteristics Characteristic Performance Req...

Страница 299: ...ng specification as listed in the Official Journal of the European Communities Low Voltage Directive 73 23 EEC EN 61010 1 1993 Safety requirements for electrical equipment for measurement control and laboratory use Approvals UL1244 Standard for Electrical and Electronic Measuring and Testing Equipment CAN CSA C22 2 No 231 Safety Requirements for Electrical and Electronic Measuring and Testing Equi...

Страница 300: ...ed in IEC 1010 1 Note Rated for indoor use only Table A 13 Safety Standards Category Standards U S Nationally Recognized Testing Laboratory Listing UL1244 Standard for Electrical and Electronic Measuring and Testing Equipment Canadian Certification CAN CSA C22 2 No 231 Safety Requirements for Electrical and Electronic Measuring and Test Equipment European Union Compliance Low Voltage Directive 73 ...

Страница 301: ...ions 40 miles distant have been received with a wire paper clip straightened and inserted directly into the input connector CAUTION The spectrum analyzer can be damaged by static discharge or high level signals Remove any static charge before connecting a wire or antenna to the spectrum analyzer Remove any static charge by first momentarily grounding the wire to the case of the instrument If the w...

Страница 302: ...Appendix B Broadcast AM FM and TV Signal Sources B 2 2715 User Manual ...

Страница 303: ...1ST The second aural carrier must be 200 kHz to 2 550 MHz greater than the first aural carrier 300HZ FILTER NOT INSTALLED 2715 cannot detect presence of 300 Hz filter ADDITIONAL NVRAM NOT INSTALLED Occurs when accessing a file located in extended NVRAM if the 2715 cannot detect the presence of the extended NVRAM AMPL NORM SUGGESTED VR PIN DAC Perform amplitude normalization Contact your local Tekt...

Страница 304: ...resentative if message persists CANNOT COUNT VCO IF Perform frequency normalization Either the VCO counter input or the IF counter input failure can cause this error to occur Contact your local Tektronix service center or representative if message persists CANNOT COUNT BEAT FREQUENCY Perform frequency normalization Contact your local Tektronix service center or representative if message persists C...

Страница 305: ...15 cannot detect the presence of the communications port COMMAND NOT IMPLEMENTED Feature not installed on this instrument COUNTER FREQUENCY UNSTABLE Perform normalizations again Frequency counter or input to it is unreliable Contact your local Tektronix service center or representative if message persists COUNTER NOT INSTALLED 2715 cannot detect the presence of the counter DATA ERROR IN FILE Firmw...

Страница 306: ...ve if message persists DISCONNECT INPUT SIGNAL Input signal needs to be removed in following step DISPLAY LINE OFF SCREEN The display line is out of range either at the top or bottom of the CRT display EDITING BUFFER IS EMPTY The local editing buffer for either the UDP or antenna tables is empty If you are attempting to delete the editing buffer the error message is simply to inform the you that t...

Страница 307: ...access correction data This failure is usually due to a corrupted or missing flatness correction data file FORMATTING PLOT Downloading plot file to hardcopy device FREQ OUT OF RANGE NORMALIZATIONS Perform frequency normalization again Contact your local Tektronix service center or representative if message persists FREQ NORM SUGGESTED 1ST LO Perform frequency normalization Contact your local Tektr...

Страница 308: ...ould be the invocation of a user defined routine while in the user defined routine acquisition mode The acquisition mode must be exited before any routine can be activated FUNC NOT AVAIL ON THIS CHAN TYPE A function was invoked on a signal which the channel table thinks is of an inappropriate type to be performed on this signal FUNCTION NOT AVAIL IN LIN MODE Switch to LOG mode vertical scale to ob...

Страница 309: ...FF Firmware hardware error Contact your local Tektronix service center or representative if message persists INTERRUPT FAULT Firmware hardware error Contact your local Tektronix service center or representative if message persists INVALID DEVICE NUMBER Firmware hardware error Contact your local Tektronix service center or representative if message persists INVALID FILE NUMBER Firmware hardware err...

Страница 310: ...e is no constant frequency modulation on the carrier NO QUIET VIDEO LINES FOUND Quiet lines are retrace lines where no modulation is present The Carrier to Noise and Composite Second Order tests use quiet lines to take in service measurements The 2715 was unable to automatically find quiet lines to use for the tests NO REFERENCE DEFINED A function was invoked which requires a valid current referen...

Страница 311: ...t be on to employ desired function NORMALIZATION COMPLETE Normalization routine successfully finished NORMALIZATION SUGGESTED Frequency normalization needed Contact your local Tektronix service center or representative if message persists NORMALIZED RESULT OUT OF RANGE Perform normalizations again Contact your local Tektronix service center or representative if message persists NORMALIZING Normali...

Страница 312: ...viously protected settings only the waveforms are saved OUT OF RANGE A value has been entered that is outside the permitted range The instrument will default to the closest permissible value If the message appears at times other than data entry a firmware hardware error is probable Contact your local Tektronix service center or representative if message persists PLOT ABORTED A new plot request has...

Страница 313: ...annot detect presence of real time clock REFERENCE LEVEL HAS NEW RANGE LIMITS The reference level range limits have changed because the preamp or external ATTEN AMPL mode is activated The reference level itself does not change REFERENCE NORMALIZATION FAILED Perform the reference normalization again checking for the presence of the correct external reference frequency and its correct entry from the...

Страница 314: ... transac tions involving the instrument settings No deletions occur in the general operation Contact your local Tektronix service center or representative if message persists SHORT HOLDOFF MODE NOT INSTLD 2715 cannot detect presence of Short Holdoff feature SHORT YIG DELAY GO TO UTIL 5 4 The YIG oscillator settling delay time has been changed from the factory default setting of 5000 ms Use the Uti...

Страница 315: ...OMPLETE Firmware routine finished SIGNAL SEARCH IN PROCESS Firmware routine running STAND BY A delay is required in the use of the instrument until this message disappears START FREQUENCY CHANGED A change in the stop frequency necessitated a change in the start frequency STOP FREQUENCY CHANGED Change in start frequency necessitated a change in stop frequency STORAGE REGISTER EMPTY No data yet stor...

Страница 316: ... an uncalibrated state has been corrected and exited UNCAL ON A change of state indicator briefly displayed when an uncalibrated state has been entered UNDEFINED ERROR CODE Firmware hardware error Returned error code has overrun established limits Contact your local Tektronix service center or representative if message persists UNDEFINED EVENT CODE Firmware hardware error Returned error code has o...

Страница 317: ...cale choices also available from the front panel VERT SCALE function block Demodulator choices are found with DEMOD 1 and DEMOD 2 WAIT ABORTED SWEEP NOT ARMED Requested WAIT FOR END OF SWEEP was aborted immediately to avoid an endless wait loop This error occurs if WAIT is requested while in single sweep mode with the sweep not armed WARNING USING EMPTY ANT TABLE The table called for is empty The ...

Страница 318: ...Appendix C System Messages C 16 2715 User Manual ...

Страница 319: ...equency setting is RESET Reset Category Each setting belongs to one RESET CATEGORY such as center frequency belongs to the fragile reset category The categories are described later in this appendix Reset Cycle An operation that causes one of the RESET CATEGORIES to be operated on Retain The opposite of RESET A setting is RETAINED for a particular RESET CYCLE if its value can be set to any allowabl...

Страница 320: ...r RS 232 configuration H Real Time Clock Configuration H Audio Alert Setting H Settings Protect Mode H Signal Search Parameters These are settings that are reset during some cycles and retained during others The settings are reset as follows H During an INITIALIZE INSTRUMENT SETTINGS cycle settings are reset to the values retained at the last physical power down H During a POWER DOWN UP cycle sett...

Страница 321: ...quency Tuning Increment H Tabular Tuning Table H Frequency Offset H Frequency Offset Mode ON OFF H Input Menu Items H Input Impedance H Reference Level Units H External Gain Attenuation H External Gain Attenuation Mode ON OFF H dBµV M Measurement Distance H dBµV M Antenna Table H dBµV M Target Waveform H Sweep Trigger Menu Items H Video Sync Polarity H Video Line Triggering Mode CONTINUOUS KNOB EN...

Страница 322: ...s are reset to user defined power up if it exists otherwise settings are reset to default values H During RECALL LAST POWER DOWN cycle settings are reset to last power down settings H During RECALL FACTORY DEFAULT POWER UP settings are reset to the factory default settings H During RECALL USER DEFINED POWER UP and RECALL NUM BERED SETTINGS cycles settings are reset to the specified settings storag...

Страница 323: ...ides standard video signals to the input of the modulator whose output is accurately measured using the 2715 The 2707 External Tracking Generator allows you to make swept frequency measurements on devices such as filters Simply insert an SMA to SMA cable between the LO IN connector on the rear of the 1405 or J101 IN on the rear of the 2207 and J101 on the rear of the 2715 You can also superimpose ...

Страница 324: ...u could apply the gated CW to the 2715 input while triggering externally with the gating signal The 2715 would then perform a spectral sweep only when the CW signal was present at its input To trigger the 2715 externally connect the external trigger signal to the EXT TRIG connector and select item 2 EXTERNAL from the Sweep Trigger menu Turn the LEVEL control fully counter clockwise and then rotate...

Страница 325: ...4 Not Used 15 Not Used Bulleted instructions in the signal discussions guide you through applications using the Accessory Connector signals The instructions are designed to be used consecutively as provided The signals are discusssed in logical sequence not in pin number order 100 0MHZ AUTO SWEEP ATTN 10DB 28 8DBMV VF WIDE 20 0MHZ 10 DB 5MHZ RBW AUTO CALIBRATOR Pin 1 enables you to introduce an ex...

Страница 326: ...s meaningful is the sweep speed The sweep speed is initially the speed in effect before you switched to EXTERNAL source in this case 50 ms division The only information in the right readout that is meaningful is the bottom line EXT 175MV indicating that the external EXT input is being used with a vertical scale factor of 175 mV div H Press 10 5 1 three times and notice that the scale changes to 87...

Страница 327: ...rouble triggering because of the multiple signal peaks and blanking period of the video signal but there should be a spectrum on the oscilloscope similar to the one on the 2715 If not adjust your oscilloscope trigger and vertical position controls Pin 2 of the Accessory Connector contains the sweep gate The sweep gate is a 5 V pulse whose leading edge is synchronous with the start of the 2715 s sw...

Страница 328: ...he spectrum analyzer settings The oscilloscope horizontal scale factor equals the 2715 span division times the ratio of the 2715 and oscilloscope sweep speeds Pin 4 of the Accessory Connector is the sweep ramp The sweep ramp varies linearly from 1 3 V to 1 3 V and is proportional to the horizontal position of the sweep as it crosses the screen The start of the ramp is synchronous with the start of...

Страница 329: ...haking protocols and other matters of importance to digital communications are detailed in the 2714 2715 Programmer Manual and the pertinent standards 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Shield Gnd 011 ATN Logic Gnd Gnd 09 Gnd 010 Gnd 07 Gnd 08 NDAC NRFD SRQ IFC D101 D106 D102 D105 D108 D107 Gnd 06 REN EOI DAV D103 D104 Figure E 3 IEEE Standard 488 GPIB Connector Pin Ass...

Страница 330: ...nual and the pertinent standards 5 9 6 1 TXD DTR GND RI CTS DCD DSR RTS RXD Figure E 4 RS 232 C Connector Pin Assignments The RS 232 connector J104 on the 2715 is typically used to connect the 2715 to a PC that is running the Cable TV RF Measurements Software The RS 232 connector on the PC interface card may be one of three types H 9 pin female H 25 pin female H 25 pin male Check which type of con...

Страница 331: ...ector Table E 1 9 Pin Female to9 Pin Female Null Modem Cable 9 Pin Female to 9 Pin Female Pin signal Pin signal 1 8 DCD CTS to 7 RTS 2 RXD to 3 TXD 3 TXD to 2 RXD 4 DTR to 6 DSR 5 GND to 5 GND 6 DSR to 4 DTR 7 RTS to 1 8 DCD CTS 8 see pin 1 9 not used 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 9 Pin Female 9 Pin Female To 2715 To PC Figure E 5 9 Pin Female to 9 Pin Female Null Modem Cable 9 Pin Female to...

Страница 332: ...o pin 7 on the 9 pin female connector Table E 2 9 Pin Femaleto25 Pin Female Null Modem Cable 9 Pin Female to 25 Pin Female Pin signal Pin signal 1 8 DCD CTS to 4 RTS 2 RXD to 2 TXD 3 TXD to 3 RXD 4 DTR to 6 DSR 5 GND to 7 GND 6 DSR to 20 DTR 7 RTS to 5 8 CTS DCD 8 see pin 1 9 not used 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 9 Pin Female 25 Pin Female 25 To ...

Страница 333: ...Accessories and Options for the part number Table E 3 9 Pin Femaleto25 Pin Male Extension Cable 9 Pin Female to 25 Pin Male Pin signal Pin signal 1 DCD to 8 DCD 2 RXD to 3 RXD 3 TXD to 2 TXD 4 DTR to 20 DTR 5 GND to 7 GND 6 DSR to 6 DSR 7 RTS to 4 RTS 8 CTS to 5 CTS 9 not used 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 9 Pin Female 25 Pin Male 25 To PC or Mode...

Страница 334: ...Appendix E External Input and Output E 12 2715 User Manual ...

Страница 335: ...nt Cover 103 0045 00 Adapter Connector N Male to BNC Female 50 103 0301 00 Adapter 75 Female F to Female BNC 103 0310 00 Adapter 75 Female to Female F Table F 2 Optional Accessories Tektronix Part Number Description 012 1339 00 Coaxial cable 75 BNC to BNC 24 in 609 6 mm 012 0074 00 Coaxial cable 75 BNC to BNC 42 in 1066 8 mm 012 0057 01 Coaxial cable 50 BNC to BNC 42 in 1066 8 mm 012 0991 01 GPIB ...

Страница 336: ...vice Kit 337 2775 01 CRT Light Filter clear 337 2775 02 CRT Light Filter gray 070 9096 00 Service Manual 016 0792 02 Transit Case Table F 3 Power Cord Identification Plug Configuration Normal Usage Option Number North America 125 V Standard Europe 230 V A1 United Kingdom 230 V A2 Australia 230 V A3 North America 230 V A4 Switzerland 230 V A5 ...

Страница 337: ...the UTIL menu The 24 pin port connector is located on the rear panel of the 2715 Connector terminations can be found in Appendix E External Input and Output or in the Programmer Manual For programming instructions refer to the Programmer Manual To configure the GPIB port see System Configuration in Section 6 of this manual Option 05 supplies a Tektronix 2707 Tracking Generator for swept measure me...

Страница 338: ...ents on devices such as filters Option 30 provides the hardware for installing the 2715 in a standard 19 in 426 6 mm rack The rackmount adapter requires minimum vertical space of 5 25 in 133 35 mm An alternate cradle mount adapter is also available see Option 34 The 2715 meets all electrical and environmental specifications when it is mounted according to the procedures accompanying Option 30 Opti...

Страница 339: ...Glossary and Index ...

Страница 340: ......

Страница 341: ...he brightness of the signal relative to the baseline portion of the display Calibrator A signal generator producing a specified output used for calibration purposes Carrier Carrier Signal The electrical signal typically a sine wave upon which modulation is impressed Carrier Frequency The frequency of the carrier signal Carrier to Noise Ratio C N The ratio of carrier signal power to average noise p...

Страница 342: ...f the input signal magnitude to the resultant output indication The ratio may be expressed in terms of volts rms per division decibels per division watts per division or any other specified factor Depth of Modulation The difference between the maximum and the minimum of the RF envelope amplitude expressed as a percentage of the maximum RF envelope level Digitally Averaged Display A display of the ...

Страница 343: ...oltage Display Reference Level A designated vertical position representing a specified input level The level may be expressed in dBm volts or any other units Distortion Degradation of a signal often a result of nonlinear operations resulting in unwanted signal components Harmonic and intermodulation distortion are common types Dynamic Range The maximum ratio of the levels of two signals simultaneo...

Страница 344: ...f the input signal and the frequency displayed expressed as a ratio Frequency Marker An intensified or otherwise distinguished spot on a spectrum analyzer display indicating a specified frequency point Frequency Modulation FM The process or result of a process in which the frequency of an electrical signal the carrier is varied in accordance with some characteristic of a second electrical signal t...

Страница 345: ...nalyzer A type of spectrum analyzer which scans the input signal by sweeping the incoming frequency band past one of a set of fixed RBW filters and measuring the signal level at the output of the filter Hum Modulation Modulation distortion at power frequencies hum is the amplitude distortion of the desired signal caused by the modulation of these signals at the frequency of the power source Hum Si...

Страница 346: ...ocal Oscillator LO An oscillator which produces the internal signal that is mixed with an incoming signal to produce the IF signal Markers The instrument uses three types of markers Update Marker Marks the current sweep position in a digital storage display as the display is being updated Video Markers Marker signals applied to the external VID MARKER input from a Tektronix 1405 Television Sideban...

Страница 347: ...g multiple memory sections which can be displayed separately or simultaneously Noise Unwanted random disturbances superimposed on a signal which tend to obscure it Noise Floor The self noise of an instrument or system that represents the minimum limit at which input signals can be observed The spectrum analyzer noise floor appears as a grassy baseline in the display even when no signal is present ...

Страница 348: ...t of the input pulse and whose amplitude is proportional to that of the peak amplitude of the input pulse Reference Level The signal level required to deflect the CRT display to the top graticule line Relative Display Flatness The display flatness measured relative to the display amplitude at a fixed frequency within the frequency span expressed in decibels Residual FM Incidental FM Short term dis...

Страница 349: ...olution bandwidth Single Sweep Operating mode in which the sweep generator must be reset for each sweep Especially useful for obtaining single examples of a signal spectrum Signal Identifier A means to identify the spectrum of the input signal when spurious responses are possible Span Per Division Span Div Frequency difference represented by each major horizontal division of the graticule Spectrum...

Страница 350: ...ed more specifically to mean a base band zero carrier frequency television signal Video Filter A postdetection low pass filter View Display Enables viewing of contents of the chosen memory section e g View A displays the contents of memory a View B displays the contents of memory B Visual Carrier Level The rms voltage of a channel s visual picture carrier considered as a sine wave at the peak of t...

Страница 351: ...5 34 AUTO 3 9 RES BW 3 9 4 13 SWEEP 3 9 Auto Res BW 4 13 Automatic Mode 5 64 Auxiliary Operations 5 68 Line Modulation 5 69 Listen 5 70 View Modulation Field 5 68 View Picture 5 69 Average Noise Measuring 6 45 AVERAGE POWER Measurement 5 20 B B C MINUS A See Subtracting Stored Signals Backspace Key 3 6 Built in Speaker 2 10 C Calibrator Built in 2 10 Calibrator Turning On and Off 6 4 CARRIER LEVEL...

Страница 352: ...alent Decibel Voltage Values 6 12 Procedure 6 12 Using 6 10 Dedicated Controls 2 8 Default Settings restoring 2 6 DEMOD Menu 6 56 Listening to AM or FM Transmissions 6 58 Listening to AM Transmissions 6 57 Listening to FM Transmissions 6 56 Video Demodulation 6 58 DESIRED to UNDESIRED measurement 5 35 Diagnostics and Adjustments 6 78 Display Line and Limit Detector 6 40 Display Registers 4 21 Anal...

Страница 353: ...UENCY RESPONSE 5 43 Mode 1 5 43 Mode 2 5 43 Function Blocks 2 8 Fundamental Controls 2 8 Fundamental Operations Channel Entry 4 4 Frequency Entry NonCATV Mode 4 7 Frequency Entry Normal Mode 4 5 REF LEVEL 4 9 SPAN DIV 4 2 G General CATV 2714 Mode Channel Tables 5 6 5 10 Selecting a Channel Table 5 6 5 7 Signal Types 5 4 General CATV 2715 Mode 5 4 GPIB Configuration 6 69 EOI LF MODE 6 70 GPIB ADDRE...

Страница 354: ...ng to AM or FM Transmissions 6 58 M Mains Power 2 3 Manually Scanning 6 89 Marker Control 4 26 Marker Peak Find 3 4 Marker to the Reference Level 6 21 Marker Moving to the Next Higher or Lower Peak 6 20 Markers Transposing 6 18 Markers to Set Start and Stop Frequencies 6 17 MAX HOLD A B 3 7 4 26 MAX Key 3 5 Max Span 4 3 Maximum Signal Levels 5 2 Measurement ADJACENT CHANNEL LEAKAGE 5 47 AURAL FM D...

Страница 355: ...Mode Frequency Entry 4 5 Normalization File 6 76 Normalization Initial 2 5 Normalizing the 2715 6 65 Numeric Keys 3 6 NVRAM If You Lose 6 81 O Occupied Bandwidths OBW Measuring 6 50 Offsets Frequency 6 26 Options Confirming Installed 6 77 Oscillator YIG See YIG oscillator Oscilloscope Trigger Modes 6 83 P Packaging 2 1 Parameter Value Enter 6 3 PEAK FIND 3 4 4 33 Phaselock Turning On and Off 6 72 ...

Страница 356: ...Reference 2 15 Setting Start and Stop Frequencies 6 17 Setting the RF Attenuation 6 4 Setting the Signal Threshold 6 22 Settings and Displays Save and Recall 6 62 Settings Files 6 76 Settings Factory Default 2 4 Signal Bandwidths Measuring 6 44 Signal Search 6 48 Signal Threshold Setting 6 22 Signal Track 4 31 Signal Track Mode 3 3 Signal Type Measurements 5 5 5 8 Signal Types 5 4 SINGLE 3 9 Singl...

Страница 357: ...npacking 2 1 USER DEF Menu 6 89 User Defined Power Up Settings 6 62 Program UDP Files 6 76 Routine Create 6 90 Settings 6 63 Using Markers to Set Start and Stop Frequencies 6 17 UTIL Menu 6 60 Diagnostics and Adjustments 6 78 Generating a Service Request 6 82 Instrument Configuration Sending Waveforms To a Computer 6 72 Settings the MInimum Signal Size 6 72 Manual Adjustments Aligning the Display ...

Страница 358: ...Index Index 8 2715 User Manual Y YIG Oscillator Changing Settling Delay Time 6 79 Minimum Acceptable Settling Time 6 79 Settling Delay Time Default 6 78 Z ZERO Key 3 5 Zero Span 4 4 ...

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