HP 8112A Operating, Programming And Servicing Manual page 225

Servicing the Shaper and Outp ut Amplifier
Theory of Operation
Introduction
Bus Latch
Shaper IC
The shaper and output amplifier circuits are located on the main
board Al and are divided into the following parts:
•
Bus Latch
•
Shaper IC
•
Current Mirror
•
Pre-Attenuator
•
Signal Output Amplifier
•
Output Attenuator
•
Trigger Output Amplifier
•
Level Check Circuit
These circuits are the last in the signal path.
An eight line decoder U500 latches data from the data bus when
enabled by WS2/LRC
the data to the shaper IC where it is used to control pulse
shaping/correction and to select output mode and complement .
The data is also applied to the pre-attenuator where it controls the
attenuation and output disable functions via relays K500 to K504.
The shaper IC U40 1 , shown in Figure 10.4- 1 ,is a high-performance
signal-control circuit which, depending on the state of its mode
(
inputs pins 22 and 23) , produces outputs as shown in Table 10.4- 1 .
Servicing the Shaper and Output Amplifier 10.4-1
(
sent by the microprocessor) and outputs
1 0 . 4