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55

Notch Filter Alignment

This procedure aligns the six notch filters. The procedure describes
alignment of a single filter, the procedure is identical for all six filters.
This alignment should be done only if the notch filter check in the
PERFORMANCE TESTS section of the manual has failed.

1)  Set the function generator for 200  mV pk-pk sine wave.

2)  In CAL MENU 1 (press BSP and TIME keys simultaneously) set the

FS700's attenuators for 64 dB.  Look at the LORAN OUTPUT on
the scope.  Set the notch filters to the middle of their range.
Remove jumper JP104 and attach the function generator to the right
pin of the jumper (viewed from the front).  Install jumpers JP105,
JP106, and JP107 (these are out in normal operation).  This
configuration bypasses the FS700's 100 kHz bandpass filter.

3)  Set one filter to its lowest frequency (40 or 110 kHz). Set the

function generator to the same frequency.

4)  Adjust the two filter inductors (L107 and L108, for example) to

minimize the signal output.

5)  Set the function generator to the maximum filter frequency (90 or

220 kHz).  Tune the filter to minimize its output.

6)  Adjust the trim capacitors (C119C-F, for example) to minimize the

signal output.

7)  Set the filter to its midrange.

8)  Repeat this procedure for the rest of the filters.

9)  Set the filters to their extremes (40 and 220 kHz).

10) Install jumper JP104 and remove JP105, JP106, and JP107.

Содержание FS710

Страница 1: ...DARD MODEL FS710 Distribution Amplifier 1290 D Reamwood Avenue Sunnyvale California 94089 Phone 408 744 9040 Fax 408 744 9049 email info thinkSRS com www thinkSRS com Copyright 1997 by SRS Inc All Rig...

Страница 2: ......

Страница 3: ...ations Found 18 Status Timing 18 Signal Quality 18 Tracking Point Monitoring 18 Notch Filters 19 Tuning the Notch Filters 19 Search Problems 20 Tracking Problems 21 Frequency Generation and Calibratio...

Страница 4: ...Output 59 Front Panel LED s Switches 59 Unregulated Power Supplies 59 Power Supply Regulators 60 Active Antenna 60 FS700 Component Parts List 61 FS710 Amplifier FS710 10 MHz AGC Distribution Amplifie...

Страница 5: ...r to remove the fuse Remove the small printed circuit board and select the operating voltage by orienting the printed circuit board to position the desired voltage to be visible when pushed firmly int...

Страница 6: ...o the lead in cable The piece of supplied special heat shrink tubing should be applied over the cable connection and heated with a heat gun or other heat source to weatherproof the connection The new...

Страница 7: ...v...

Страница 8: ...ency Stability Long Term 10 12 the same as LORAN C transmitter Cesium clock Short Term 10 10 standard oscillator 10 11 low phase noise option 10 MHz Outputs 4 outputs 1 Volt peak to peak sine wave int...

Страница 9: ...OUTPUT for frequencies between 100 kHz and 10 MHz Phase Resolution 3 Interface GPIB IEEE 488 compatible interface All instrument functions may be controlled General Operating 0 to 50 C Power 100 120...

Страница 10: ...cked NSTA Returns the number of stations found during search STON Returns the noise margin of the station being tracked TIME h m s Sets reads the time of day TLCK Returns the amount of time the FS700...

Страница 11: ...uring normal operation TST Starts self test and returns status when done ASC i Sets antenna input source i 0 antenna i 1 cal DAT Reads In phase and Quadrature gate data GAT i Sets test gate patterns I...

Страница 12: ...he STATUS section is on It will take 20 minutes for the internal 10 MHz oscillator to stabilize At that point the OVEN LED will turn off It is not necessary to wait for the OVEN LED to turn off before...

Страница 13: ...sen for stable propagation characteristics and low ground wave attenuation The transmissions of the various stations are differentiated by the timing of their pulses The LORAN transmitters in a specif...

Страница 14: ...g the transmitter carrier frequency and the pulse emission time The pulse emission time is controlled by accurately setting the emission time of the third positive zero crossing of the LORAN rf pulse...

Страница 15: ...osphere is reflected by the ionosphere and returns to earth Because the height of the ionosphere depends on the time of day the season and solar activity the skywave propagation path and the propagati...

Страница 16: ...N C chain information mailing list LORAN C station propagation delays may also be obtained from 2 United States Coast Guard Headquarters Washington D C 20593 202 267 0283 The LORAN C specifications ma...

Страница 17: ...Northeast USA 99600 s M Seneca New York USA W Caribou Maine USA X Nantucket Massachussetts USA Y Carolina Beach NC USA Z Dana Indiana USA Canadian East Coast 59300 s M Caribou Maine USA X Nantucket M...

Страница 18: ...Petropavlo Russia X Attu Alaska USA Y Aleksandrovsk Russia North Pacific 99900 s M Saint Paul Pribilof Is Alaska USA X Attu Alaska USA Y Point Clarence Alaska USA Z Narrow Cape Alaska USA Gulf of Ala...

Страница 19: ...7...

Страница 20: ...8...

Страница 21: ...with the FS700 Signal Acquisition After the user chooses and enters the desired GRI the FS700 will acquire the LORAN C signal the SEARCH LED will turn on First automatic gain control AGC software adju...

Страница 22: ...stantaneous frequency offset to change the phase Thus a FLL will have better phase noise and short term stability than a PLL The time constant of the FS700 s FLL is set according to the signal to nois...

Страница 23: ...FIELD key causes the cursor to cycle through the available choices If the FS700 is in GPIB remote mode pressing the FIELD key returns the unit to local mode 4 Menu Keys The menu keys control which men...

Страница 24: ...Features 1 Power Entry Module The power entry module contains the FS700 s fuse and the line voltage selection card Be sure that the fuse rating matches that listed on the rear panel and that the line...

Страница 25: ...eceiver is locked LOCK LED on This output is a transistor with a 10 kohm pull up resistor This output may be wire or d with other similar outputs as long as the current sink capability is greater than...

Страница 26: ...e set in the TRACKING menu while tracking status is displayed in the STATUS menu Overview Most of the FS700 s operation is completely automatic First choose a GRI and enter it into the FS700 Refer to...

Страница 27: ...herwise the secondary may be set to an index of A B C D or E the order of transmission of the secondaries The identification of the secondaries is determined by the timing of the secondaries relative...

Страница 28: ...units of GRI The time constant is adjusted using the cursor keys and can be set between 128 and 16384 GRI The time constant sets the amount of signal averaging and the time between corrections of the...

Страница 29: ...n that the FS700 made to its oscillator The time average of this value is zero The oscillator has a sensitivity of about 1 x 10 11minimum step size Also displayed is the instantaneous phase of the FS7...

Страница 30: ...the quality of the received signal and any transient conditions that may have occurred The letters a r b n and o indicate the status of antenna rf blink noise margin and oscillator warnings If the let...

Страница 31: ...e FS700 is locked or searching use a rf spectrum analyzer and look at the signal from the LORAN OUTPUT BNC Because the FS700 s LORAN OUTPUT can only drive a high impedance load and most spectrum analy...

Страница 32: ...n This is because the most common problem is some type of transient interference confuses the FS700 The detectable errors during the search phase are No Stations Found This error means that the FS700...

Страница 33: ...S700 will terminate its lock and display a timeout error message If the search mode is set to AUTO the FS700 will restart the acquisition process Otherwise it will stop When one of these conditions oc...

Страница 34: ...lock is terminated This error should rarely occur if at all and is easily corrected by adjusting the oscillator s coarse frequency adjustment screw see TROUBLESHOOTING section of manual This error can...

Страница 35: ...0 01 V degree 3 6 V full scale The output is digitized with a 8 bit A D converter limiting the resolution to 3 for a 1 sec measurement The analog output is of course continuous The FS700 can measure a...

Страница 36: ...the total elapsed time and the total signal phase shift for up to 32767 hours From this data the frequency offset is continuously calculated and updated once a second Thus the frequency difference ov...

Страница 37: ...olling the data display back and forth using the up and down arrow keys The most recently received character is marked by a solid rectangle character The second screen controls the contrast of the FS7...

Страница 38: ...26...

Страница 39: ...the up and down arrow keys The character most recently received is marked by a rectangular block character Command Syntax Communications with the FS700 use ASCII characters Commands may be in either U...

Страница 40: ...ters and commands that would cause the FS700 to become unlocked are classified as execution errors Detailed Command List The four letter mnemonic in each command sequence specifies the command The res...

Страница 41: ...ry stations in different chains transmit in different orders look in the station list to determine which secondary station index 1 2 3 4 5 corresponds to which station V W X Y Z If i 1 the FS700 is se...

Страница 42: ...index of the station to which the FS700 is currently locked The correspondence of returned values to the LORAN stations is shown in the table below Because the secondary stations in different chains t...

Страница 43: ...an 100 kHz the value 9 9 E 99 is returned The value 1 0 E0 is returned if the frequency ratio is greater than 1 The parameter i selects either the result of the 1 sec measurement i 0 or the result of...

Страница 44: ...y source The answer is returned in degrees with 0 1 degree resolution If an input signal is not present or the output frequency is set to less than 100 kHz the value 999 is returned PCLR The PCLR comm...

Страница 45: ...o 1 the three status enable registers will be cleared on power up If this bit is set to 0 the registers will retain the values they had at power down This allows the generation of power on service req...

Страница 46: ...word Each low high word pair taken together forms a 32 bit 2 s complement integer that is the summed integrator data GAT i The GAT command sets test patterns of the pattern generator gates If i 0 all...

Страница 47: ...byte has been set 4 MAV The output buffer is non empty 5 ESB An unmasked bit in the standard event status byte has been set 6 SRQ MSS SRQ service request bit 7 Warmed Up Set when oscillator warmup per...

Страница 48: ...ad or the CLS command is received LORAN Status Byte bit Name Usage 0 Search Error Set if an error occurs during station search such as no stations found desired station not found etc 1 Time Out Set if...

Страница 49: ...37...

Страница 50: ...manual for information In the example below the FS700 is installed as a device named LORAN Once all the hardware and GPIB drivers are configured use IBIC This terminal emulation program allows you to...

Страница 51: ...nf tstr d i convert answer to integer if i 3 searching or locked printf Already searching n exit 0 ibwrt FS700 GRIP 99400 10 set GRI to west coast USA ibwrt FS700 AUTO 0 6 Set set search mode to MANUA...

Страница 52: ...IBINIT1 60000 IBINIT2 IBINIT1 3 BLOAD bib m IBINIT1 110 CALL IBINIT1 IBFIND IBTRG IBCLR IBPCT IBSIC IBLOC IBPPC IBBNA IBONL IBRSC IBSRE IBRSV IBPAD IBSAD IBIST IBDMA IBEOS IBTMO IBEOT IBRDF IBWRTF IB...

Страница 53: ...41...

Страница 54: ...rror message The messages that may be displayed are listed below System ROM Test FAIL This message will occur if the FS700 determines that the contents of its ROM are no longer the same as originally...

Страница 55: ...The default GPIB address is 17 and it is a good idea to use this number in writing programs Any address in the range of 0 to 30 may be set in the SETUP menu The FS700 will ignore its front panel when...

Страница 56: ...7 This should produce an output at the DAC between 3 V and 3 V Each bit change produces an 92 mV step The DAC should be accurate to 30 mV 2 of setting RF Circuitry Tests To test the RF circuitry a 100...

Страница 57: ...ns difference in position 50 steps 10 s 1 cycle of input The integrator output data has an ADC range of 128 to 127 corresponding to 5V to 5V In either gate position stepping the gate position through...

Страница 58: ...uch as SRS SR620 4 Precision voltmeter with AC bandwidth of at least 100 kHz such as Fluke 8840A 5 10 MHz frequency source known to be more accurate than 1 x 10 8 6 Antenna Input Termination Adapter S...

Страница 59: ...cope and measure the amplitude with the AC voltmeter The amplitude should be 0 4 vrms 0 3 This is the nominal amplitude Record this number on the test sheet 3 Set the frequency to 90 kHz and record th...

Страница 60: ...f a single filter Check to be sure that the notch moves over the appropriate range Check that the depth of the notch is at least 20 dB Record the notch depth Return the filter to its extreme 4 Repeat...

Страница 61: ...within 1 x 10 5 of their setting Record the results 2 Set the synthesizer to 100 1 kHz 0 5 V pk pk and attach to the FS700 s OSC IN BNC 3 Set the FS700 s FREQUENCY OUTPUT to 100 kHz Look at the PHASE...

Страница 62: ...ass Notch Filter Tests Filter 1 Notch _________ Nominal 20 dB Filter 2 Notch _________ Nominal 20 dB Filter 3 Notch _________ Nominal 20 dB Filter 4 Notch _________ Nominal 20 dB Filter 5 Notch ______...

Страница 63: ...51 100 1 kHz Offset 9 9 E 4 _________ 1 1 E 3 99 9 kHz Amplitude _____ Fail _____ Pass 99 9 kHz Offset 1 1 E 3 _________ 9 9 E 4...

Страница 64: ...B 3 Precision Frequency Counter with at least 1 x 10 9 resolution such as SRS SR620 4 Antenna Input Termination Adapter Schematic is shown in TROUBLESHOOTING section Figure 1 Coarse Oscillator Adjustm...

Страница 65: ...ys simultaneously set the oscillator DAC to 0 4 Measure the 10 MHz output from the FS700 and adjust the oscillator coarse adjustment screw until the counter reads within 1 x 10 8 of 10 MHz Bandpass Fi...

Страница 66: ...of equal height and spaced symmetrically about 100 kHz at about 82 and 118 kHz See Figure 1 4 Adjust L115 so there is only a slight 5 dip in the passband L114 may need to be tweaked to remove any pass...

Страница 67: ...rator to the right pin of the jumper viewed from the front Install jumpers JP105 JP106 and JP107 these are out in normal operation This configuration bypasses the FS700 s 100 kHz bandpass filter 3 Set...

Страница 68: ...56...

Страница 69: ...es can be tuned in the 40 90 kHz range All of the notch filters are of the same design and the references in the following description apply to the first notch filter The filters are designed to provi...

Страница 70: ...s lost power for the RAM is provided by a lithium battery through blocking diode D202 and R201 Also the chip select line for the RAM is disabled on power down by the RESET line through Q201 This preve...

Страница 71: ...e integrating capacitor switch U403A is kept closed until just before a gate occurs The charge on the integrating capacitor is buffered to the analog to digital converter multiplexer by U402 The ampli...

Страница 72: ...trol the contrast of the front panel LCD This voltage is buffered and multiplied to 5 V by U605A The other half of U603 is an 8 bit A D converter used to digitize the four gated integrator outputs the...

Страница 73: ...d and filtered by R824 R816 and C808 and AC coupled through C807 R829 is a pull down to satisfy the antenna error detection circuitry Front Panel LED s Switches p 10 14 The front panel LED indicators...

Страница 74: ...olt regulated outputs The output of these regulators drops to about 1 25 volts when the front panel power switch SW901 is opened This also turns off the 5 V supply as the drive and reference for 5 V i...

Страница 75: ...thic Ceramic 50V 20 Z5U C 20 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 21 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 22 5 00225 548 1U AXIAL Capacitor Ceramic 50V 80 20 Z5U AX C 23 5...

Страница 76: ...Ceramic 50V 20 Z5U C 131 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 133 5 00134 529 100P Cap Monolythic Ceramic 50V 20 Z5U C 201 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 202 5 00225...

Страница 77: ...5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 816 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 817 5 00065 513 01U Capacitor Mylar Poly 50V 5 Rad C 818 5 00065 513 01U Capacitor Mylar Poly...

Страница 78: ...U AX C 947 5 00225 548 1U AXIAL Capacitor Ceramic 50V 80 20 Z5U AX C 948 5 00225 548 1U AXIAL Capacitor Ceramic 50V 80 20 Z5U AX C 949 5 00225 548 1U AXIAL Capacitor Ceramic 50V 80 20 Z5U AX C 950 5 0...

Страница 79: ...Ceramic 50V 20 Z5U C 994 5 00023 529 1U Cap Monolythic Ceramic 50V 20 Z5U C 995 5 00225 548 1U AXIAL Capacitor Ceramic 50V 80 20 Z5U AX C 996 5 00225 548 1U AXIAL Capacitor Ceramic 50V 80 20 Z5U AX C...

Страница 80: ...ariable L 116 6 00060 606 22MH Inductor Variable L 117 6 00065 606 12MH Inductor Variable L 118 6 00066 606 8 2MH Inductor Variable L 119 6 00028 604 10UH Inductor Vertical Mount L 120 6 00028 604 10U...

Страница 81: ...sistor Carbon Film 1 4W 5 R 117 4 00352 401 1 6K Resistor Carbon Film 1 4W 5 R 118 4 00352 401 1 6K Resistor Carbon Film 1 4W 5 R 119 4 00352 401 1 6K Resistor Carbon Film 1 4W 5 R 120 4 00186 407 4 2...

Страница 82: ...n Film 1 4W 5 R 406 4 00027 401 1 5K Resistor Carbon Film 1 4W 5 R 407 4 00021 401 1 0K Resistor Carbon Film 1 4W 5 R 408 4 00188 407 4 99K Resistor Metal Film 1 8W 1 50PPM R 409 4 00027 401 1 5K Resi...

Страница 83: ...arbon Film 1 4W 5 R 715 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 716 4 00031 401 100 Resistor Carbon Film 1 4W 5 R 717 4 00585 401 36 Resistor Carbon Film 1 4W 5 R 718 4 00080 401 47 Resistor Car...

Страница 84: ...Metal Film 1 8W 1 50PPM R 906 4 00439 407 1 33K Resistor Metal Film 1 8W 1 50PPM R 907 4 00149 407 121 Resistor Metal Film 1 8W 1 50PPM R 908 4 00042 401 15K Resistor Carbon Film 1 4W 5 R 909 4 00034...

Страница 85: ...303 3 00044 340 74HC244 Integrated Circuit Thru hole Pkg U 304 3 00046 340 74HC374 Integrated Circuit Thru hole Pkg U 305 3 00046 340 74HC374 Integrated Circuit Thru hole Pkg U 306 3 00046 340 74HC374...

Страница 86: ...ltage Reg TO 220 TAB Package U 902 3 00141 329 LM337T Voltage Reg TO 220 TAB Package U 903 3 00114 329 7815 Voltage Reg TO 220 TAB Package U 905 3 00116 325 78L05 Transistor TO 92 Package U 906 3 0018...

Страница 87: ...1 00047 130 14 PIN IDP Connector Male Z 0 1 00051 171 20 COND Cable Assembly Ribbon Z 0 1 00066 112 7 PIN 24AWG WH Connector Amp MTA 100 Z 0 1 00073 120 INSL Connector BNC Z 0 1 00144 131 14 PIN DIF P...

Страница 88: ...8 613 NE 2H Lamp Z 0 7 00411 720 FS700 12 Fabricated Part Z 0 9 00255 917 FS700 ANTENNA Product Labels Z 0 9 00326 907 3 4 BLK ADHES Shrink Tubing Z 0 9 00329 908 1495 Adhesives Z 0 9 00330 908 CATALY...

Страница 89: ...om a FS700 receiver Figure 1 FS710 Front Panel TYPICAL SPECIFICATIONS INPUT Frequency 10 MHz 100 kHz Type Insulated BNC transformer coupled Impedance 50 or 75 jumper selectable Level 35 mV to 5 VAC pe...

Страница 90: ...C107 R105 C108 C109 and L102 U2 controls the gain of U1 by comparing the peak voltage at L102 with the reference voltage from P1 R117 and R118 D1 indicates loss of signal red if the control voltage fr...

Страница 91: ...501 56P Capacitor Ceramic Disc 50V 10 SL C 102 5 00002 501 100P Capacitor Ceramic Disc 50V 10 SL C 103 5 00002 501 100P Capacitor Ceramic Disc 50V 10 SL C 104 5 00023 529 1U Cap Monolythic Ceramic 50V...

Страница 92: ...TO 92 Package Q 5 3 00021 325 2N3904 Transistor TO 92 Package Q 6 3 00021 325 2N3904 Transistor TO 92 Package Q 7 3 00021 325 2N3904 Transistor TO 92 Package Q 8 3 00197 321 2N2907 Transistor TO 18 Pa...

Страница 93: ...4W 5 R 114 4 00071 401 33 Resistor Carbon Film 1 4W 5 R 115 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 116 4 00079 401 4 7K Resistor Carbon Film 1 4W 5 R 117 4 00350 407 3 74K Resistor Metal Film...

Страница 94: ...82 Z 0 7 00120 720 SR440 2 Fabricated Part Z 0 7 00331 709 FS710 1 Lexan Overlay Z 0 9 00267 917 GENERIC Product Labels...

Страница 95: ...83 Figure 2 FS710 PC Layout...

Страница 96: ...84...

Страница 97: ...85...

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