Table of Contents
Advertisement
Check A3 ADC MUX Function Block (steps 1-4)
1. Connect the positive lead of a
pin 6. This measures the sampling oscillator tune voltage which is an input to the A3
interface assembly ADC MUX.
2. Set the spectrum analyzer to the following settings:
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OHz
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389.5 MHz
Trigger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single
3. Use the data entry keys to tune the CENTER FREQ to the values listed in Table 11-4.
4. As the sampling oscillator frequency is increased, the DVM reading should also increase.
If the tune voltage is correct, but the ADC measures the voltage and determines it to be
out of specification, troubleshoot the A3 assembly ADC MUX.
Check A14J301 10 MHz reference input (steps 5-8)
5. Disconnect W37 from A14J301.
6. Connect a test cable from W37 to the input of another spectrum analyzer. Tune the other
spectrum analyzer to the following settings:
Center frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..lO MHz
Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..2MHz
7. The amplitude of the 10 MHz reference signal should measure >-1 dBm. If the signal
does not measure >-1 dBm, troubleshoot the 10 MHz distribution on Al5 and A21
OCXO (If not Option 103).
8. Reconnect
to
W37
to
DVM
Table 11-4. Center Frequency Tuning Values
HP 85623
Center Frequency (MHz)
2156.3
2199.5
2230.3
799.3
2263.3
2282.3
2302.3
2155.3
2158.3
2336.3
2196.3
1.3
2378.3
2410.3
2422.3
pin 13 and the negative lead to
sampling
Oscillator Frequency (MHz)
285.000
286.364
287.500
288.462
288.889
290.000
290.909
291.667
292.500
293.478
294.444
295.000
296.000
296.471
297.000
297.222
Synthesizer Section
1 l-9
Advertisement
Chapters
Table of Contents
