Adjustment Procedures
5-26 2715 Spectrum Analyzer Service Manual
HOption 50 instruments - Connect a 50 Ωcoaxialcable to the signal
generator output. Connect the Power meter head to the other end of
the 50 Ωcoaxial cable. Set the generat or to a 100 MHz signal.
Adjust the signal amplitude to -30.0 dBm, then connect the 100
MHz signal to the RF INPUT.
d. Adjust R200 on the RF Mother board (see Figure 5--4 on page 5--16) to
position the signal peak at the top graticule line.
e. Turn offthe input signal (Carrier Off), and enable the internal calibrator
by pressing INPUT 9.
f. Adjust R170 on the Reference Oscillatorboard (see Figure 5--7)to
position the calibrator signal peak at the top graticule line.
R170
CALLevel
Figure 5- 7: CAL Level Adjustment on Reference Oscillator Board
6. Adjust the FM Detector (C357 and R153 on the Log board)as follows:
a. Disable the internal calibratorby pressing INPUT 9.
b. Apply a 100 MHz/-- 30 dBm signal with 80 kHz FM deviationat a 1 kHz
rate to the RF INPUT.
c. Reset the VERT SCALE to 10 dB/div and centerthe display by pressing
CTR-MEAS/TRKG. Enable ZERO SPAN; select theinternal trigger by
pressing SWP/TRIG1; enable FM Deviation Mode by pressing APPL 7;
then set the sweep speed to 200 s by pressing SWEEP ↓repeatedly until
200 sisdisplayed.
d. Set the inner LEVEL control for a triggered display.
e. Set R153 on the Log board to set the signal peak approximatelyone
division from the bottom of the screen.
f. Adjust C357 on the Log board for maximum signal size.
g. Adjust R153 on the Log board to place the bottom of thesignal at the
bottom graticule line.
h. Reduce the amount of deviation in 10 kHz increments until the bottom
peaks of the signal are at one division below top of screen.