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Appendix D: Application Note

D–2

1502C MTDR User Manual

Relationships

Z

O

= (138 /

 p

κ

 

)* 

(log

10 

D / d) for coaxial cable

%

= 

r

 

*

100

VSWR = (1 + 

r

) + (1 –

 r

) for the case where VSWR is the same for all

frequencies

c

= 30 cm / nanosecond = 0.984 ft / ns

V

F

= 1 / 

p

κ

V

P

= 30 / 

p

κ

 cm / ns = 0.984 / 

p

κ

 ft /ns

C

= 7.36 

κ

 + (log

10

 D / d)

L

= 140 log

10

 D / d

1 in

= 2.54 cm

1 ft

= 30.48 cm

1 m

= 3.28 ft

VSWR vs. Percent Reflected Voltage

To find the Voltage Standing Wave Ratio (VSWR), knowing the percent reflected
voltage (%), or vice versa, use the Frequency Domain Conversions section of the
slide rule (see Figure D–1).

0

2

4

6

8

10

12

14

16

18

20  %

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35 1.40 1.45 1.50 VWSR

80

75 70 65 60 55 50 45 40 35 30 25 20 15 10 5

0

.01 .02.03 .05 .10

.2 .3

.5 .7 1.0

2 3

5 7 10

20

50

100 %

30

SINGLE

RESISTIVE

DISCONTINUITY

ONLY

RETURN LOSS

(IMPULSE ONLY)

1.04 VSWR = 2% REFLECTION

20% = 1.5 VSWR

Figure D–1: Slide Rule of VSWR vs. Percent Reflected Voltage

On the upper scale, locate the known value of VSWR (or %). Adjacent to that
point is the corresponding value for % (or VSWR). VSWR is the peak-to-valley
ratio of standing sine waves.

Содержание 070-7169-05

Страница 1: ...c i a n sw i t ho v e r 1 5 0y e a r so f s p e c i a l i z a t i o n 9 0d a yw a r r a n t y 5d a yr i g h t o f r e t u r no na l l e q u i p me n t 1 3y e a r w a r r a n t i e sf o r n e wa n d p...

Страница 2: ...User Manual 1502C Metallic Time Domain Reflectometer 070 7169 05 This document applies for firmware version 5 04 and above www tektronix com...

Страница 3: ...and foreign patents issued and pending Information in this publication supercedes that in all previously published material Specifications and price change privileges reserved Tektronix Inc P O Box 50...

Страница 4: ...tions 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...

Страница 5: ...select option 1 Service support 1 800 833 9200 select option 2 Technical support Email techsupport tektronix com 1 800 833 9200 select option 3 1 503 627 2400 6 00 a m 5 00 p m Pacific time This phone...

Страница 6: ...eform Up Close 2 5 A Longer Cable 2 7 Ohms at Cursor 2 8 Noise 2 11 Set Ref Delta Mode 2 13 VIEW INPUT 2 17 STORE and VIEW STORE 2 18 VIEW DIFF 2 20 Menu Accessed Functions 2 21 TDR Questions and Answ...

Страница 7: ...Return Loss dB vs Percent Reflected Voltage D 3 Percent Reflected Voltage vs Characteristic Line Impedance D 4 Percent Reflected Voltage vs Load Resistance D 6 Characteristic Line Impedance or Load Re...

Страница 8: ...oss 1 18 Figure 1 15 Ohms at Cursor 1 19 Figure 1 16 Display with VIEW INPUT Turned Off 1 20 Figure 1 17 Display of a Stored Waveform 1 20 Figure 1 18 Display of a Stored Waveform 1 21 Figure 1 19 Wav...

Страница 9: ...ected Pulse 2 10 Figure 2 14 Noise on the Waveform 2 11 Figure 2 15 Noise Reduced 2 12 Figure 2 16 Noise Reduced to Minimum 2 12 Figure 2 17 Incident and Reflected Pulses with Cursor at 0 00 ft 2 13 F...

Страница 10: ...r Division B 8 Figure B 12 Waveform Centered Cursor at 0 000 ft B 9 Figure B 13 Pulse Centered on Display B 9 Figure B 14 Cursor on Lowest Major Graticule that Rising Edge crosses B 10 Figure B 15 Cur...

Страница 11: ...bles Table i Shipping Carton Test Strength ix Table 1 1 Fuse and Voltage Ratings 1 2 Table 1 2 Vp of Various Dielectric Types 1 12 Table A 1 Electrical Characteristics A 1 Table A 2 Environmental Char...

Страница 12: ...strip chart recorder which installs into the front panel Option Port The 1502C may be operated from an AC power source or an internal lead acid battery that supply a minimum of five hours operating ti...

Страница 13: ...y way of the grounding conductor in the power cord is essential for safe operation The AC power connector is a three way polarized plug with the ground earth lead connected directly to the instrument...

Страница 14: ...Install the front cover on the 1502C and surround the instrument with polyethylene sheeting to protect the finish 3 Cushion the instrument on all sides with packing material or urethane foam between t...

Страница 15: ...General Information x 1502C MTDR User Manual...

Страница 16: ...sult in injury or loss of life CAUTION Caution statements identify conditions or practices that could result in damage to this product or other property Terms on the Product DANGER indicates an injury...

Страница 17: ...r cords are rated for indoor use only Use only a power cord that is in good condition Refer cord and connector changes to qualified service personnel To avoid fire hazard use only a fuse of the correc...

Страница 18: ...n the battery to us for recycling the battery cases must be intact the battery should be packed with the battery terminals insulated against possible short circuits and should be packed in shock absor...

Страница 19: ...General Safety Summary xiv 1502C MTDR User Manual...

Страница 20: ...ry storage temperature should be between 35 C to 65 C In the field the 1502C can be powered using the internal battery See Figure 1 1 For AC operation check the rear panel for proper voltage setting T...

Страница 21: ...hese instructions concerning the care of the battery pack They contain instructions that reflect on your safety and the performance of the instrument The 1502C can be powered by a rechargeable lead ge...

Страница 22: ...fter exposure to these extreme conditions turn the instrument off and remove the AC power cord The battery pack should be stored within a temperature range of 35 C to 65 C However the self discharge r...

Страница 23: ...continued discharge of the batteries When the instrument is stored at temperatures below 10 C voids might develop in the liquid crystal display LCD These voids should disappear if the instrument is p...

Страница 24: ...1 3 1502C Front Panel Controls CAUTION Do not connect live circuits to the CABLE connector Voltages exceeding 5 volts can damage the pulser or sampler circuits Bleed the test cable of any residual sta...

Страница 25: ...0 mr 0 2 ft ac 0 00 ft Power Type Waveform Cursor Front Panel to Cursor Distance Window Selected Noise Filter Selected Vertical Scale Selected Distance per Division View Input Indicator View Store Ind...

Страница 26: ...ndard instrument defaults to ft div A metric instrument Option 05 defaults to m div but either may be changed temporarily from the menu The default can be changed by changing an internal jumper see 15...

Страница 27: ...strument memory If a waveform is already stored pushing this button will erase it The settings of the stored waveform are available from the first level menu under View Stored Waveform Settings Menu S...

Страница 28: ...ow the vertical gain of the instrument is displayed You may choose decibels or millirho When powered down the instrument will default to millirho when powered back up d Distance Div Is ft m Offers you...

Страница 29: ...e pixels can be alternated to test the LCD ii Response Time Diagnostic generates alternate squares of dark and light reversing their order This tests the response time of the LCD and can give an indic...

Страница 30: ...es while communicating with those computers With user developed software drivers the ability to obtain detailed error messages during the development can be very useful For more information contact yo...

Страница 31: ...affected All Vp settings should be set for the cable under test not the supplied jumper cable Table 1 2 Vp of Various Dielectric Types Dielectric Probable Vp Jelly Filled 64 Polyethylene PIC PE or SPE...

Страница 32: ...r a sample three foot cable O F F O F F O F F O N ac 3 000 ft Figure 1 5 Vp Set at 30 Cursor Beyond Reflected Pulse Set Too Low O F F O F F O F F O N ac 3 000 ft Figure 1 6 Vp Set at 99 Cursor Less Th...

Страница 33: ...ly e g 20 ft cable would occupy four divisions on the LCD if 5 ft div was used The entire cable should be displayed O F F O F F O F F O N ac 0 000 ft Figure 1 8 20 ft Cable at 5 ft div If the cable le...

Страница 34: ...F O F F O F F O N ac 20 000 ft Open Figure 1 10 Open in the Cable 3 To find the distance to the fault or end of the cable turn the n o POSITION control until the cursor rests on the leading edge of t...

Страница 35: ...ft Short Figure 1 12 455 ft Cable A rise or fall is a signature of an impedance mismatch fault A dramatic rise in the pulse indicates and open A dramatic lowering of the pulse indicates a short Varia...

Страница 36: ...ctions so rho is equal to zero A good cable that is terminated in its characteristic impedance is close to ideal and will appear as a flat line on the 1502C display Small impedance changes like those...

Страница 37: ...ls 6 Press MENU twice to return to normal operation To measure return loss with the 1502C adjust the height of the reflected pulse to be two divisions high and read the dB return loss directly off the...

Страница 38: ...The 51 3 W measure ment by itself is only specified to be accurate to 10 The series resistance of the cable to the point at the cursor affects the accuracy of the impedance measurement directly In a...

Страница 39: ...EW INPUT on O F F O F F O F F ac 0 000 ft O F F Figure 1 16 Display with VIEW INPUT Turned Off When pushed the STORE button puts the current waveform being displayed into memory If already stored push...

Страница 40: ...waveform NOTE If the two waveforms are identical e g if STORE is pushed and VIEW DIFF is immediately pushed the difference would be zero Therefore you would see the difference waveform as a straight...

Страница 41: ...eform cannot be moved on the display 3 Move the current waveform the one you want to compare against the stored waveform to the center of the display 4 Push VIEW STORE and the stored waveform will app...

Страница 42: ...useful when you want to see any changes in the cable In some systems there might be several reflections coming back from each branch of the network It might become necessary to disconnect branch lines...

Страница 43: ...on the LCD will show set D 2 Turn the n o POSITION control to set the cursor where you want to start the distance reading This will be the new zero reference point For a three foot lead in cable the c...

Страница 44: ...xit HORZ SET REF use the following procedure a Turn the NOISE FILTER control to HORZ SET REF b Turn DIST DIV to 1 ft div If the distance reading is extremely high you might want to use a higher settin...

Страница 45: ...l scale and press STORE Figure 1 26 Incident Pulse at Three Divisions 3 Push STORE 4 Return NOISE FILTER to the desired setting Notice that the vertical scale now reads 500 mr div NOTE The millirho ve...

Страница 46: ...3 Turn NOISE FILTER to VERT SET REF 4 Adjust VERT SCALE so the reflected pulse from open at far end of cable sample is two divisions high O F F O F F O F F O N ac 19 200 ft set vertical scale and pre...

Страница 47: ...the sample cable impedance To measure reflections on a 50 W cable the VERT SET REF must be reset 8 To exit VERT SET REF use the following procedure a Turn NOISE FILTER to VERT SET REF b Adjust VERT SC...

Страница 48: ...connector 2 Push MENU to access the main menu 3 Scroll to Setup Menu and push MENU again 4 Scroll to Acquisition Control Menu and push MENU again 5 Scroll to Max Hold is Off and push MENU again This...

Страница 49: ...instrument returns to normal operation This feature puts the 1502C in a listening mode by turning off the pulse generator 1 Attach a cable to the 1502C front panel CABLE connector 2 Push MENU to acces...

Страница 50: ...ction with Max Hold is On 7 To exit Pulse is Off access the Acquisition Control Menu again turn the pulse back on then repeatedly push MENU until the instrument returns to normal operation The single...

Страница 51: ...O F F O F F O F F ac 0 000 ft O F F Figure 1 33 A Captured Single Sweep 8 To exit Single Sweep is On access the Acquisition Control Menu again turn the Single Sweep back off then repeatedly push MENU...

Страница 52: ...nts might show a cable as good the 1502C can show many previously hidden faults You the Operator The 1502C is a highly accurate cable tester It is easy to use and will provide fast accurate measuremen...

Страница 53: ...ou can get a general idea from the table on page 1 12 or find the Vp with a sample piece of cable using the procedure on page 1 12 or use the Cable Information Menu If it is impossible to obtain the V...

Страница 54: ...n the rising edge of the reflected pulse O F F O F F O F F O N ac 3 000 ft Incident Pulse Reflected Pulse Figure 2 2 Cursor of Rising Edge of Reflected Pulse The upper right corner should read 3 000 f...

Страница 55: ...ce See the pulse take a dive That is the classic signature of a short a point of lower impedance O F F O F F O F F O N ac 3 000 ft Short Figure 2 4 Waveform with Short The distance window still reads...

Страница 56: ...is the incident pulse as sent from the pulse generator see Figure 2 5 The second step is the reflected pulse as it bounces back from the end of the cable The reflected pulse and the time between pulse...

Страница 57: ...5 mr Adjust the n o POSITION control to keep the middle portion of the pulse on the display The bumps following the incident pulse are the aberrations from the internal circuitry and reflections betwe...

Страница 58: ...vg VERT SCALE 500 mr DIST DIV 50 ft 25 m Vp appropriate setting for your cable 2 With these settings we can view the entire cable By placing the cursor at the rise of the reflected pulse we can see th...

Страница 59: ...1502C front panel controls CABLE available longer cable NOISE FILTER 1 avg VERT SCALE 500 mr DIST DIV 50 ft 25 m Vp 66 or whatever your cable is 2 Press MENU 3 Scroll to Setup Menu and press MENU agai...

Страница 60: ...ac 59 5 W 408 000 ft Ohms at Cursor Readout Figure 2 10 Ohms at Cursor 7 Turn the n o POSITION control to set the cursor near the beginning of the cable In this example the ohms at cursor reading is 5...

Страница 61: ...cursor reading is now 1 W O F F O F F O F F O N ac 1 W 2 000 ft Figure 2 13 Ohms at Cursor Beyond Reflected Pulse If the cursor is placed too near a fault the reflection will not have stabilized which...

Страница 62: ...40 000 ft 2 Attach the 50 W terminator to the end of the test cable using the female to female BNC adaptor both of these items are supplied with the instrument 3 Increase VERT SCALE to 1 00 mr Use th...

Страница 63: ...Reduced to Minimum 6 Move the n o POSITION control and notice how averaging restarts at a low value to allow easy positioning The 50 W terminator was used here because it gives a good impedance match...

Страница 64: ...LE 500 mr default DIST DIV 1 ft div 0 25 m NOTE If the POWER was left on from the previous step return the distance window reading to 0 000 ft with the n o POSITION control O F F O F F O F F O N ac 0...

Страница 65: ...racted from the distance calculations You have set zero at the far end of the test cable O F F O F F O F F O N ac 0 000 ft D Figure 2 19 New Zero Set at End of Test Cable 6 To change the HORZ SET REF...

Страница 66: ...le loss The reflection from an open or a short at the far end of a long cable is often less than two divisions high at 500 mr div This is because of the energy lost in the cable Here is how to correct...

Страница 67: ...re must be taken in changing the VERT SET REF because of the calibration change The 1502C automatically starts the pulse at two divisions high When you change the vertical reference you essentially de...

Страница 68: ...FILTER 1 avg VERT SCALE 500 mr DIST DIV 1 ft div 0 25 m 2 Press VIEW INPUT The indicator block on the LCD should read OFF and the waveform should disappear from the display O F F O F F O F F ac 0 000...

Страница 69: ...e the waveform in the upper section of the display O F F O F F O N ac 0 000 ft O N Figure 2 24 Waveform Moved to Upper Portion of the Display 3 Press STORE The indicator block should become highlighte...

Страница 70: ...ou stored previously with the open cable and the current waveform with the shorted cable O N ac 0 000 ft O N O N O FF O F F Stored Waveform VIEW STORE Current Waveform VIEW INPUT Figure 2 26 Waveform...

Страница 71: ...eform O N ac 0 000 ft O N O N O FF O N Difference VIEW DIFF Figure 2 27 Stored Current and Difference Waveforms NOTE There must be a waveform stored before it can be compared by the VIEW DIFF function...

Страница 72: ...he Main Menu 4 Using the n o POSITION control scroll down to Setup Menu 5 Press MENU to accept this selection 6 Scroll down to Acquisition Control Menu 7 Press MENU to accept this selection 8 Scroll d...

Страница 73: ...15 With a clip lead or other device short the far end of the test cable then remove the short Note that both conditions now appear on the display O N ac 0 000 ft O N Figure 2 29 Short and Open Viewed...

Страница 74: ...t of the day shorting out on a tree limb During the night the cable cools tightens and is no longer shorted on the tree limb 18 To exit Max Hold access the Acquisition Control Menu again turn off Max...

Страница 75: ...l Menu again scroll to Pulse is Off and press MENU to turn the pulse back on Repeatedly press MENU until the instrument returns to normal operation 1 Set the 1502C front panel controls to CABLE Attach...

Страница 76: ...far end of the test cable 12 Press VIEW INPUT The 1502C has done a single sweep capturing just one frame O F F O N ac 0 000 ft O N O F F Figure 2 33 Captured Single Sweep of Shorted Test Cable 13 Remo...

Страница 77: ...l materials A5 No Electricity is like light its velocity is affected by the material through which it passes Q6 What is that difference called A6 The relative velocity of propagation Vp The velocity o...

Страница 78: ...What factors determine the resistance of a cable A10 The cross sectional area gauge length and the type of material the conductor is made of usually copper Q11 What factors determine the impedance of...

Страница 79: ...Operator Tutorial 2 28 1502C MTDR User Manual...

Страница 80: ...ed with a splashproof chart printer Refer to the YT 1 YT 1S Chart Recorder Instruction Manual that comes with this option for instructions on operation paper replacement and maintenance Refer to the t...

Страница 81: ...Assembly 200 3737 00 Precision 50 W Test Cable S N B010298 012 1350 00 50 W BNC Terminator 011 0123 00 BNC Connector female to female 103 0028 00 Slide Rule Calculator 003 0700 00 Slide Application No...

Страница 82: ...o UHF female 103 0032 00 Connector BNC female to Type F male 103 0158 00 Connector BNC male to Type F female 013 0126 00 Connector BNC female to GR 017 0063 00 Connector BNC male to GR 017 0064 00 Ter...

Страница 83: ...Options and Accessories 3 4 1502C MTDR User Manual...

Страница 84: ...ise 0 5 peak beyond 10 feet Excluding front panel aberrations Jitter 0 02 feet 40 ps peak to peak Vp set to 0 99 DIST DIV set to 0 1 ft div At 23 4 feet to 46 8 feet jitter is 0 04 feet Output Impedan...

Страница 85: ...n velocity relative to air Range 0 30 to 0 99 Resolution 0 01 Accuracy Within 1 Included in total timebase error tolerance Custom Option Port Tektronix Chart Recorders YT 1 and YT 1S are designed to o...

Страница 86: ...o 55 Hz 0 013 inch p p MIL T 28800C Class 3 Shock Mechanical Pulse 30 g 11 ms 1 2 sine wave total of 18 shocks MIL T 28800C Class 3 Bench Handling MIL STD 810 Method 516 Procedure V Operating 4 drops...

Страница 87: ...bpart B Class A Limits Safety Standards U S Nationally Recognized Testing Laboratory Listing UL1244 Standard for electrical and electronic measuring and test equipment Canadian Certification CAN CSA C...

Страница 88: ...ronment Temporary condensation occurs only when the product is out of service Pollution Degree 3 Conductive pollution or dry nonconductive pollution that becomes conductive due to condensation These a...

Страница 89: ...Appendix A Specifications A 6 1502C MTDR User Manual...

Страница 90: ...recision terminator 011 0123 00 3 foot precision coaxial cable 012 1350 00 Disconnect any cables from the front panel CABLE connector Connect the instrument to a suitable power source a fully charged...

Страница 91: ...IV 1 ft div 0 25 m Vp 66 If the instrument fails this check it must be repaired before any distance measurements can be made with it 1 Turn the 1502C power on The display should look very similar to F...

Страница 92: ...the cable The distance shown on the display distance window upper right corner of the LCD should be from 2 87 to 3 13 feet 0 875 to 0 954 m O N ac 3 000 ft O F F O F F O F F Figure B 3 Cursor at End...

Страница 93: ...the distance window shows a distance greater than 2 000 feet 600 m The waveform should be a flat line from the pulse to this point O F F O F F O F F O N ac 2051 000 ft Figure B 5 Flat Line Display Ou...

Страница 94: ...ossible Not all of the waveforms will be viewable at all gain settings 1 Using the n o POSITION control verify that the entire waveform can be moved to the very top of the display off the graticule ar...

Страница 95: ...at deal of noise reduction can be made using the NOISE FILTER control 1 Adjust the n o POSITION control to obtain 100 000 ft 30 500 m in the distance window O N ac 100 000 ft O F F O F F O F F Figure...

Страница 96: ...failure message is displayed if the 3 limit for any combination of gains over the three ranges is exceeded 2 Exit from Offset Gain Diagnostic but do not leave the Service Diagnostic Menu yet If the in...

Страница 97: ...sing the n o POSITION control move the top of the pulse to the center graticule line O F F O F F O F F O N ac 1 872 ft Figure B 10 Top of Pulse on Center Graticule 5 Set the DIST DIV control to 0 2 ft...

Страница 98: ...e n o POSITION control clockwise O F F O F F O F F O N ac 0 000 ft Figure B 12 Waveform Centered Cursor at 0 000 ft If the risetime is out of specification it might be difficult to make accurate short...

Страница 99: ...ajor Graticule that Rising Edge crosses 5 Using the n o POSITION control and noting the distances displayed verify that the distance between the points where the leading edge crosses the highest and l...

Страница 100: ...Watch the leading edge of the pulse move and verify that this movement is less than five pixels or 0 02 ft 0 006 m O F F O F F O F F O N ac 1 624 ft Jitter Figure B 16 Jitter Apparent on Leading Edge...

Страница 101: ...test the major functional blocks of the instrument that could prevent you from being able to make measurements It is possible for the front panel controls or the LCD to have problems that would inter...

Страница 102: ...hree clicks turn the PULSE WIDTH knob all the way counterclockwise remove any accessories that might be plugged into the Option Port e g chart printer and disconnect any cable that might be attached t...

Страница 103: ...ms Turn instrument off immediately to avoid possible damage to LCD display If error message s appear follow the displayed instructions Using VOM check for near zero Ohms in fuse Is waveform missing er...

Страница 104: ...ry annoying because the Option Port is checked once each time the TDR gets a waveform If the TDR is being controlled by or through the Option Port device you will probably have to remove that device a...

Страница 105: ...t 2 Divs at 0 dB At power on during initialization only The instrument expects the pulse height to be slightly less than two major divisions high This message indicates that the pulse is greater than...

Страница 106: ...ent attempts to center the pulse before making it two divisions high These messages indicate that the waveform could not be properly placed on the display This usually means that the offset or gain ci...

Страница 107: ...hes for a point on the leading edge of the pulse that is on the cable inside the instrument about 10 up the pulse This message indicates that the search failed This could be because the pulse is not t...

Страница 108: ...Constant vs Velocity Factor H Time vs Short Distance in centimeters or inches any dielectric H Time vs Long Distances in meters or feet any dielectric Terms and Symbols RS Source Resistance of a sign...

Страница 109: ...lected voltage or vice versa use the Frequency Domain Conversions section of the slide rule see Figure D 1 0 2 4 6 8 10 12 14 16 18 20 1 00 1 05 1 10 1 15 1 20 1 25 1 30 1 35 1 40 1 45 1 50 VWSR 80 75...

Страница 110: ...5 40 35 30 25 20 15 10 5 0 01 02 03 05 10 2 3 5 7 1 0 2 3 5 7 10 20 50 100 30 SINGLE RESISTIVE DISCONTINUITY ONLY RETURN LOSS IMPULSE ONLY 1 REFLECTION 40 dB RETURN LOSS Figure D 2 Slide Rule of Retur...

Страница 111: ...lection division r division 100 to 80 1r to 0 8r 20 20 80 to 40 0 8r to 0 4r 10 10 40 to 16 0 4r to 0 16r 5 05 16 to 8 0 16r to 0 08r 2 02 8 to 4 0 08r to 0 04r 1 01 4 or less 0 04 r 0 5 005 1r W 03r...

Страница 112: ...0 90 60 50 45 40 35 30 25 20 15 10 5 75W 80 70 65 60 55 50 45 40 35 30 70 65 60 55 76 74 73 72 70 69 68 67 66 65 64 63 71 75W 1 74 73 72 71 70 69 34 40 46 46 40 34 RETURN LOSS dB 20 division downward...

Страница 113: ...flection should be positioned vertically to a known 50 W reference level For a reference level use either a section of line of known impedance ahead of the line under test load or use a termination of...

Страница 114: ...reflection with a plateau will appear as a spike Centimeters vs Inches or Meters vs Feet Inches and Centimeters A given number of inches can be converted to centimeters by placing the point on the sl...

Страница 115: ...e meters or 10 feet use the INCHES and CENTIMETERS scale 1 0 INCHES CENTIMETERS ONE WAY DISTANCE TO OR BETWEEN FAULT SPLICE CONNECTOR LOAD END OR OTHER IMPEDANCE DISCONTINUITY 6 7 8 1 5 2 0 3 4 Distan...

Страница 116: ...scale just below it and follow the same procedure as above METERS FEET ONE WAY DISTANCE TO OR BETWEEN FAULT SPLICE CONNECTOR LOAD END OR OTHER IMPEDANCE DISCONTINUITY 20 30 40 50 60 70 80 DIELECTRIC...

Страница 117: ...Appendix D Application Note D 10 1502C MTDR User Manual...

Страница 118: ...oss a distance to a load such as an antenna with minimal energy loss Most cables consist of two conductors one to deliver the electrical signal and another to act as a return path which keeps both end...

Страница 119: ...B vertical scale on our instrument refers to the amount of voltage gain amplification the instrument applies to the signal before displaying it For example when the instrument is amplifying the voltag...

Страница 120: ...erms display and LCD are often used interchangeably Millirho rho r is the reflection coefficient of a cable or power delivery system It is the ratio of the voltage reflected back from the cable or cir...

Страница 121: ...r will not allow electrical energy to flow through it These circuits are also called broken circuits The circuit is open to the air which looks like a very high impedance Precision The statistical spr...

Страница 122: ...circuit moves from one sampled voltage level to the next is called sampling efficiency If the efficiency is too low the waveforms will be smoothed or rounded If the efficiency is too high above 100 th...

Страница 123: ...rough a cable of known length can also be computed The way in which the energy is reflected and the amount of the energy reflected indicate the condition of the cable Velocity of Propagation Vp Electr...

Страница 124: ...tors BNC BNC 3 2 BNC to Alligator 3 2 BNC to Banana 3 2 BNC to Binding Post 3 2 BNC to F Type 3 2 BNC to GR 3 2 BNC to Hook Tips 3 2 BNC to N Type 3 2 BNC to UHF 3 2 Contacting Tektronix x Controls Ca...

Страница 125: ...ontrol 1 9 Backlight 1 9 Distance Division 1 9 Maximum Hold 1 9 Pulse 1 9 Single Sweep 1 9 Vertical Scale 1 9 Single Sweep 1 31 Velocity of Propagation 1 8 View Stored Waveform 1 11 N Noise 2 11 Reduc...

Страница 126: ...19 Single Sweep 1 31 2 24 Slide Rule 3 2 Specifications A 1 Electrical A 1 Environmental A 3 Physical A 4 Store 2 18 Store the Waveform 1 20 T Table of Contents i Tektronix contacting x Temperature Lo...

Страница 127: ...Index Index 4 1502C MTDR User Manual...

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