HP 8559A Operation And Service Manual page 192

5-19. LOG AMPLIFIER LOG AND LINEAR ADJUSTMENT (SERIAL PREFIX 22O8A) (Cont'd)
12. Set step attenuator to 0 dB. Digital voltmeter should indicate 800 mV, plus offset (algebraic sum)
If DVM reading is not within limits, adjust A14R2 LOG LIN adjustment for a digital voltmeter reading of
800 mV, plus offset minus 50 percent of overshoot. (Example: if DVM indicates 767 mV and should be
indicating 777 mV
(-
782 m l )
13. Repeat steps 10, 11, and 12 until the digital voltmeter indicates 800 mV plus offset
adjustment of Al4R2 in step 12.
14. Set the step attenuator to the positions shown in Table 5-7 and record DVM reading for each setting.
Correct the DVM readings by algebraically adding the offset (recorded in step 9).
Step Attenuator
Setting (dB)
15. Readjust A14R2 if necessary to meet the limits in Table 5-7.
16. Set step attenuator to
17. Set Amplitude Scale to LIN. The digital voltmeter should indicate the reading set in step 16 *25 mV. If it
does, go to step 19. If it does not, or if log fidelity is not within limits, go to step 18 and select A14R16*.
18. Select A14R16* to obtain an output in step 17 within
Log fidelity must be considered when selecting A14R16*. That is, if the
DVM READING CORRECTED FOR OFFSET in Table 5-7 is greater than 100
selected for a DVM reading greater than the reading set in step 16. If the
READING CORRECTED FOR OFFSET is less than 100 mV, A14R16* should
be selected for DVM reading less than the reading set in step 16.
ADJUSTMENTS
10 mV overshoot), adjust A14R2 for a DVM reading of 777 mV minus - 5 mV, or
TABLE 5-7. LOG FIDELITY CHECK
DVM Reading
dB and set output level of signal generator for a digital voltmeter reading of 800
1 mV.
NOTE
DVM Reading Corrected for
Min. (mV) Actual (mV)
1 mV.
1 mV with no further
Max. (mV)