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Model 8902A
Audio Detector Check
Operation
34.
35.
36.
37.
Disconnect the signal generator's audio output. Press the FM key. Set the signal generator's AM
o f f and set the FM on with a peak deviation of 50 kHz and a rate of I kHz. Press the RATIO
key then the LOG/LIN key to Yo to establish a reference of 100%. Set. DETECTOR to PEAK-.
The Measuring Receiver should display between 95 and 105% REL depending upon the signal
generator's FM distortion.
Set DETECTOR to PEAKf/2 by pressing both the PEAK+ and PEAK- keys simultaneously.
The Measuring Receiver should display a value between 100Yo and the value read in step 34.
Press the AVG key. The instrument should display between 69.3 and 72.1% REL. Turn the ratio
function o f f by pressing the RATIO
key
again.
Press the PEAK+ key then press the PEAK HOLD
key.
Switch the signal generator's FM
o f f .
The Measuring Receiver's display should retain the largest value obtained after pressing PEAK
HOLD. Turn
o f f
the peak hold function by pressing the PEAK+ key.
IF Level Check
38. Press the S (Shift) key then the IF LEVEL key (the (PM key). The Measuring Receiver should
display between 99.9 and 100. lolo.
IF Frequency and LO Frequency
39.
40.
41.
Set the signal generator to 100.000 MHz CW at 0 dBm. (Accurately set its frequency.) Press the
AUTOMATIC OPERATION key then key in 34.0 and press the SPCL key to display t h e IF
frequency. The frequency displayed should be between 1.45 and 1.55 MHz.
Key in 33.0 and press the SPCL key to display the LO frequency. The frequency displayed
shoiild be between 101.45 and 101.55 MHz.
Key in 3.1 and press the SPCL
key.
(Special Function 3.1 switches the IF bandwidth back to
455 kHz.) The frequency displayed should be between 100.44 and 100.46 MHz.
Peak Tuned RF Level and RF High-Pass Filter Check
42. Set the signal generator to 5.25 MHz CW at 0 dBm. Key in 36.0 and press the SPCL key. The
display should read between 0.500 and 2.000 -03 W (that is, between 0.5 and 2 mW).
43. Press the RATIO key. If the display is in
O/o
REL,
press the LOG/LIN key to display dB
REL.
Key in 3.3 and press the SPCL key (to insert the R F high-pass filter). The Measuring Receiver
should display between -2 and -8 dB REL. Turn
off
the ratio function by pressing the RATIO
key again. Key in 3.0 and press the SPCL key to return the R F high-pass and IF filter selection
to automatic.
Synchronous and Average Tuned
RF
Level Check
44. Set the signal generator for 20 MHz CW at 0 dBm. Press the S (Shift)
key then the TUNED R F
LEVEL key (the RF POWER key) to measure the signal using the IF synchronous detector.
When the Measuring Receiver displays a rending, press the MHz key. Press the CALIBRATE
key. Adjust the signal generator's level so the Measuring Receiver displays 0.00 dBm.
3-55
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