HP 8560A Service Manual page 66

5. DC Log Amplifier Adjustments
A4 LOG Fidelity Adjustment
This adjustment consists of adjusting A4R531 until the error is adjusted to zero.
Procedure
1. Set the HP 8560A (LINE) switch to off. Remove the analyzer cover and place the analyzer
in the service position as illustrated in Figure 2-6. See Figure 2-7 for adjustment location.
2. Connect the HP 3335 50 R output to the HP 8560A 50 R input. Set the HP 8560A (LINE)
switch on.
3. Press [m), ICAL), IF ADJ
4. Set the HP 8560A controls as follows:
C E N T E R F R E Q
SPAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .O
RES BW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 kHz
REF LVL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -1OdBm
5. Set up an HP 3335A as follows:
FREQUENCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..15MHz
AMPLITUDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -1OdBm
6. Press (MKR), MARKER DELTA
7. Calcuate the error. The error = Delta Marker reading + 16 ( in dB).
8. Set the source power to -10 dBm.
9. Adjust A4R531 ( see Figure 2-7) to read two times the error, press LCAL),
ADJ CURR IF STATE.
10. Repeat to check. Readjust as necessary to get error adjusted to zero.
2-32 Adjustment Procedures
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..15MHz
and decrease the source power to -26 dBm.