MAINTENANCE
WJ-8711A DIGITAL HF RECEIVER
7-14
5.
While observing the oscilloscope trace, slowly increase the signal generator
output level until the trace indicates a logic "0" (0V) level. Note the signal
generator output level at which the squelch output switches. Verify that the
signal generator output level is within
±
10 dB of the receiver squelch setting.
6.
Increase the receiver squelch threshold in 10 dB increments, up to 0 dBm. At
each increment, increase the signal generator output level until the
oscilloscope displays a logic "0" level, indicating that the squelch has turned
off. Note the signal generator output level at each switchpoint. Verify that at
each level tested, the signal generator output level is within
±
10 dB of the
receiver squelch setting.
7.
Set the squelch to -100 dBm [SQL 100 <Return>] and set the signal
generator to produce a 15.0000 MHz AM modulated output, at a level of -40
dBm. Set the modulation to 400 Hz, 50%.
8.
Observe that a clear 400 Hz tone is present in the headphones, and the
oscilloscope indicates a logic "0" at the squelch output terminal.
9.
While monitoring the headphone audio and the oscilloscope display, connect
a short jumper between the MUTE terminal of TB1 and ground. Observe that
the audio cuts off and after a slight delay, the squelch line switches to
Logic "1".
10.
Remove the jumper and verify that the audio, and the squelch logic level
return to the state observed in step 8.
7.6.9
RECONSTRUCTED IF OUTPUT PERFORMANCE TEST
1.
Connect the WJ-8711A Receiver and test equipment as illustrated in
Figure 7-8
.
BOONTON
92B
RF MILLIVOLT
METER
50 OHM
LOAD
RECEIVER
IF OUT
A2J1
2031
SIGNAL
GENERATOR
RF IN
RF OUT
A3J1
87IL39
Figure 7-8. Reconstructed IF Output Performance Test Equipment Connection
2.
Set the signal generator to produce a 15.0000 MHz CW output at a level of
-100 dBm.
3.
Set the RF millivoltmeter to the -20 dBm range.
Courtesy of http://BlackRadios.terryo.org
Содержание WJ-8711A
Страница 4: ...iv THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 19: ...1 i SECTION I GENERAL DESCRIPTION Courtesy of http BlackRadios terryo org...
Страница 32: ...GENERAL DESCRIPTION WJ 8711A DIGITAL HF RECEIVER 1 12 NOTES Courtesy of http BlackRadios terryo org...
Страница 33: ...2 i SECTION II INSTALLATION Courtesy of http BlackRadios terryo org...
Страница 34: ...2 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 47: ...3 i SECTION III LOCAL OPERATION Courtesy of http BlackRadios terryo org...
Страница 48: ...3 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 92: ...LOCAL OPERATION WJ 8711A DIGITAL HF RECEIVER 3 44 NOTES Courtesy of http BlackRadios terryo org...
Страница 93: ...4 i SECTION IV RS 232 REMOTE OPERATION Courtesy of http BlackRadios terryo org...
Страница 94: ...4 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 122: ...RS 232 REMOTE OPERATION WJ 8711A DIGITAL HF RECEIVER 4 28 NOTES Courtesy of http BlackRadios terryo org...
Страница 123: ...5 i SECTION V CSMA REMOTE CONTROL Courtesy of http BlackRadios terryo org...
Страница 124: ...5 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 143: ...6 i SECTION VI CIRCUIT DESCRIPTION Courtesy of http BlackRadios terryo org...
Страница 157: ...7 i SECTION VII MAINTENANCE Courtesy of http BlackRadios terryo org...
Страница 158: ...7 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 189: ...8 i SECTION VIII REPLACEMENT PARTS LIST Courtesy of http BlackRadios terryo org...
Страница 190: ...8 ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
Страница 241: ...FP i FOLDOUTS Courtesy of http BlackRadios terryo org...
Страница 242: ...FP ii THIS PAGE INTENTIONALLY LEFT BLANK Courtesy of http BlackRadios terryo org...
