HP 85027A Operating And Service Manual page 11

HP 85027A/B/C Adjustments
DC Mode RF Adjustment Check
21. On the source, turn on the RF power.
22. Set the attenuator to 0 dB.
23. On the analyzer, verify DC mode, averaging, smoothing, and the cursor are still
on. Allow the trace to settle. Press [DISPLAY] [MEAS-*MEM] [MEAS-MEM].
The cursor should now indicate 0.0 dB.
24. Set the attenuator to 30 dB.
25. The cursor should now indicate the calibrated -30 dB to within 0.8 dB.
26. If the value indicated is not within 0.8 dB of the calibrated -30 dB, it may be
necessary to adjust R5 and R29 until the difference between the 0 dB and 30
dB attenuator settings is just within 0.8 dB of the calibrated 30 dB. Adjust R5
when the attenuator setting is 0 dB and R29 when at 30 dB.
27. If any adjustments are made, it will be necessary to repeat the AC Adjustment
Procedure again, only this time using a tolerance limit of ± 0.8 dB instead of the
0.1 dB indicated in steps 8 through 11. This will allow you to split the error
difference between the two modes of operation.
28. Both AC and DC dynamic accuracy specifications should be within the limits
stated in Table 1-1.
5-4
UPDATES APPLY TO ALL SERIALS