HP 8112A Operating, Programming And Servicing Manual page 181

Instru ment Overview and Troubleshooting Guide
Theory of Operation
BURST
BURST
CLOCK
COUNTER
BURST
OPT I ON
ON
CONTROL
INPUT
ANALOG
CONTROL
TR I GGER
LEVEL
The block diagram in Figure 10.1-1 shows the HP 81 12A at a
functional level.
PERO PVC
l:ELC
PERIOD
Figure 10. 1·1. HP 8 1 1 2A Functional block diagram
The microprocessor controls the operation of the instrument by
reading inputs from the front panel keyboard or the HP-IB , and
sending the appropriate data to the Digital-to-Analog Converters
( )
DA Cs which control the generator hardware. It also updates the
front panel LEDs and display in response to the keyboard and HP-IB
inputs.
The generator hardware contains three specially developed HP ICs:
Timing IC
DISPLAY BO
KEY BOARD
W ! DC
DVC WVC !CUP
This is used as triggerable pulse generators.
Three ICs are used, taking the external
signal applied to the Control Input and
applying Period, Delay and Width control in
successive stages to provide pulses for the
Slope IC .
Instrument Overview and Troubleshooting Guide 10.1-1
1 0. 1
ICON HILC AVC
TRI GGER
AMPL IFIER
OFFSET
DAC
OVC
HILC