Low Pass Filter - HP 8112A Operating, Programming And Servicing Manual

24. Adjust A1R3 1 8 for 5.045 V -0/+20 mV RMS. Same DVM
reading as in FIXED transition mode.
Gauss Amplitude
25. Set the HP 8 1 1 2A transition to GAUSS.
26. Adjust A 1 R418 for 5 .045 V -0/+20 mV RMS . Same DVM
reading as in FIXED and LINEAR transition modes.
If
27. Use the DVM built-in filter and set the DVM to read D C
voltages. the DVM does not have a built-in fi l ter, use an
external low pass fi l ter, as shown in Figure 9-6.
28. Switch COMPL on and off, and adjust A 1 R402 to obtain
the minimum amplitude difference between the two modes
0 V ± 10 m V (Same DVM reading) .
2 9 . Set up the H P 81 12A as follows:
Transition
HIL
LOL
LIMIT
30. Set up the DVM to read AC voltages up to 20 V. Switch fi l ter
OFF or remove external fi l ter.
3 1 . Check that the amplitude for FIXED , LINEAR and GAUSS
transition mode is 8.080 V -0/+40 mV RMS .
If
3 2 . re-adjustment i s necessary, repeat Fixed, Linear and Gauss
adjustments as required.
Offset
33. Set up the HP 8 1 1 2A as follows:
HIL
LOL
34. Set up the DVM to read DC voltages up to 10 V.
35. Connect the HP 8 1 12A main output via an exact 50
feedthrough terminator to the DVM, and enable the DVM
built-in fi l ter. If the DVM does not have a built in fi l ter, use a
low-pass fi l ter as shown in Figure 9-6.
36. Adjust A2R42 for 7.95 V ± 10 mV.
37. Set up the HP 8 1 1 2A as follows:
HIL
LOL
38. Check accuracy of negative offset . DVM reading
- 7.95 V ± 30 mV.
39. Re-adjust A2R42 if necessary.
Fixed v
v
+8.0
-8.0
Off
v
v
+8.00
+7.90
v
v
- 7.90
- 8.00
Adjustment Procedures 9-17
n
0.13