HP 8112A Operating, Programming And Servicing Manual page 207

Slope Generation
FRCl1 WIDT H
GENERATOR
RAt'P
a=FACITOR : ;
'
.
Figure 1 0.3-3. Slope IC block diagram
Refer to Figure 1 0.3-5 and Figure 1 0.3-3. When triggered by the
output of the width generator, the Slope IC U301 operates in one of
two transition modes.
Fixed Transition
(
In fixed mode fixed 4.5 ns transitions
used by the Shaper IC
time output pulses.
With fi x ed mode selected, the input trigger signal on pin 1 is
passed via ECL circuitry to the EECL output , pin 2 1 . See Figure
Figure 1 0.3-3. An error output is available at pin 23, this goes active
if a trigger input is detected whilst the IC output is still active.
Linear and Gaussian Transitions
In linear and gauss slope modes, a differential output
is used to drive the Shaper IC
pulses with variable transition times.
When linear or gaussian mode is selected, the slope generator relies
on four current sources and a switched range capacitor network
to produce variable transition time leading and trailing edges,
depending on the LEE and TRE DACs in the control section
Chapter 10.5). The slope ramp value is controlled internally, or
externally, according to the condition of pin 1 0
- s . 2 v
TRI G IN
I
SQ-IMtTT TRIGCER
14 La.I LEVEL
ADJUST
+6.2V
)
, an ECL trigger output is
(
See Chapter 10.4) to produce fi x ed transition
(
See Chapter 10.4) to produce output
Servicing the Timing and 1 0.3-7
Slope Generators
CCNTRCL SIGR... .
FIXED
1 3 SLCF'E
_J
21
EECL
JUL.r
EXT
l2.srnA
OUT BIAS
R:3 1 a .
.
( )
OUT, OUT
(
See
( )
EXT .