Transition Mode And Output Control Signals; Shaper Ic Amplitude-Vernier Control-Voltage; Shaper Ic Reference Current; Shaper Ic Current-Mirror - HP 8112A Operating, Programming And Servicing Manual

Transition Mode and
Output Control Signals
Shaper IC
Amplitude-vernier
Control-voltage
Shaper IC Reference
Current
Shaper IC
Current-mirror
Pre-Attenuator and
Output Attenuator
Control Signals
Check the logic levels on shaper IC pins for each type of transition
and output mode, against Table 10.4-3:
Table 10.4-3. Waveform Control truth table
Transition WFl
Fixed
Linear
Gauss
output
Mode
COMPL
Check the amplitude-vernier control-voltage with the HP 8112A
HIL and LOL settings as indicated in Table 10.4-4. The voltage is
measured at the board connector side of R422.
Table 10.4-4. Amplitude-vernier Control-voltages
HP 8112A Setting Control voltage
Shaper IC reference current (I,,.) can be checked by measuring the
voltage across R411. The reading should be approximately 5.4 V
which equates to Iref of 2.5 mA.
Check that the signal levels at the emitters of Q400A and Q400B are
identical, as these transistors are a matched pair.
Check the relay control signals m -K4 against Table 10.4-5:
Table 10.4-5. Attenuator Control truth table
Amplitude range KO Kl K2 K3 K4
10.0
1.00 v - 9.99 v
100
Output Disabled
Servicing the Shaper and Output Amplifier
W F 2 N / C
Piu 22 Pin 23 Pin 19
H L
L L
H L
x x
X X
- -
V - 16.0 V H H
L H
H L
X
X
X
L
H
- - -
H L L
L H L
H H H
10.4-13