HP 8112A, Operating, Programming And Servicing Manual

Page: 165 / 406

Width Adjustment
Equipment
•
Counter (HP5335A)
•
Oscilloscope (HP 54121 T)
Procedure
1 . Set up the HP 8 1 1 2A as follows:
Note
Trigger Mode NORM
Control Mode Off
PER 20 ms
DEL 65 ns
WID
1 ms
Transition Fixed
HIL +3.0 v
LOL
0.0 v
COMPL Off
DISABLE Off
LIMIT
Off
2. Set the counter to TIME Interval A-+B, COM, A
f ,
B \ , Trig
level 1 .50
v,
z
=
son
3. The typical Width range characteristic is shown in Figure 9-4.
4. Connect the HP 8 1 1 2A main output to channel A of the counter.
5. Adjust the range
high end
with A2R9 for about 1 % above
programmed value ( 1 .0 1 ms).
6. Set the HP 81 12A WID parameter to 9.99 ms.
7. Adjust the range low
end
with AlRl l for about 1% above
programmed value ( 1 0 . 1 ms).
8. Set the HP 81 12A WID parameter to 3.5 ms.
9. Check the
mid range
for 3.5 ms ±50 µs.
10. Repeat steps 5 to 9, adjusting again if necessary for the best
compromise.
If the adjustment is not possible, alter the value of A2VR3/R63 (see
table 9-1 ) . Repeat steps 5 to 9 if neccessary.
1 1 . Set the HP 8 1 1 2A as follows:
PER
WID 200 ns
10 ns
12. Connect HP 81 12A Trigger Output via a 20 dB attenuator, to
trigger input of the HP 54121A.
13. Connect HP 8 1 1 2A Output via a 20 dB attenuator to input 4 of
the HP 54121A.
Adjustment Procedures 9-13