HP 8566B Adjustment Manual page 103

18. Gain Compression Test
2-76 Performance Tests
OUTPUT LEVEL RANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . -20 dBm
Care should be taken to disturb the cable assembly as little as possible,
since flexing may cause a change in the measured power level. The
power sensor should be placed near the spectrum analyzer input to
minimize flexing when the cable is moved.
3. Connect equipment as shown in Figure 2-32, with output of
synthesizer connected to power sensor. Power is measured at
the end of the cable assembly, not at the synthesizer output
connector. Adjust synthesizer output level for a power meter
indication of -25.00 dBm f0.05 dB.
4. Disconnect cable assembly from power sensor and connect free
end to spectrum analyzer RF INPUT as indicated in Figure 2-32.
Key in analyzer settings as follows:
5. Press the SCALE LIN pushbutton, then press (SHIFT) IREs]
CAL control fully clockwise.
6. Press MARKER (NORMAL) @.
7. Connect cable to power sensor and adjust synthesizer output level
for a power meter reading of -15.00 dBm f0.02 dB.
8. Reconnect cable to the spectrum analyzer RF INPUT.
9. Change spectrum analyzer
Record the MKR A amplitude:
gain error in changing the reference level from -15 dBm to -5
with 0 dB input attenuation.
[ )
10. Set
REFERENCE LEVEL
the signal trace approximately 1 division down from the reference
level line.
11. Press MARKER w, a.
12. Connect cable to power sensor and adjust synthesizer output level
for a power meter indication of -5 dBm f0.02 dB. Reconnect
cable to spectrum analyzer input.
[
13. Change
REFERENCE LEVEL
Record the MKR A amplitude:
14. Subtract the value obtained in step 9 from the value recorded
in step 13 to find the gain compression:
result should be >-1.0 dB (less than 1 dB compression).
15. Press Cm) on the spectrum analyzer. Press (SHIFT) 1-J)
[SHIFT) v[o) 0 dBm.
[ )
REFERENCE LEVEL
to -15 dBm. Adjust AMPTD CAL to place
)
to -5 dBm.
2 GHz
. . . OHz
. . . 30 Hz
. . . 3 MHz
to -5 dBm.