HP 8112A Operating, Programming And Servicing Manual page 205
50 mhz programmable pulse generator
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- Operating, programming and servicing manual (112 pages) ,
- Operating, programming and servicing manual (406 pages)
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Period, Delay and Width
Generation
Because CUR REF, FRQ IN and TIME IN are virtual earth inputs,
the external input currents can be produced by a voltage source and
series resistance. The control mode functions (PERC , DELC, WIDC)
are produced by feeding the conditioned control input voltage to the
TIME IN input of the relevant timing IC. The approximate value of
current drawn by the input current pins is shown below.
Table 1 0.3-5. Reference current input levels
Reference Current
RATE mode approx
TIME mode approx
CTRL mode approx
Outputs
The three outputs of the Timing ICs (OUT, OUT, ERROR OUT)
are all open-collector with a fixed current (HI
and a fixed transition time of 2.5 ns.
Error Output. The error output from the timing IC indicates that
a trigger signal has been received before the completion of the
previously triggered event .
Period, Delay and Width signals are generated by Timing ICs U200,
U240 and U220 respectively.
f4--
--.j
DELAY
f4--
--.j
___JLJl_ _J �
�
DOUBLE
PULSE
&
< LEE
TRE MUST BE LESS THAN WIDTH )
Figure 1 0.3-2. Example of signal generation
Period Generator
The period generator operating in the RATE mode produces 503
duty cycle square wave output pulses at a repetition rate governed
by the analog current input (from the Period DAC or Control Input)
and the internal range data.
FRQ IN
µA
mA -
80
2
0.2
µA
mA -
mA
80
2
0.2
µA
mA -
mA
80
2
0.2
f4--
PERIOD
C DELAY MUST BE LESS THAN PERIOD )
W I DTH
( W I DTH MUST BE LESS
THAN PERIOD )
--.j f4--
TRE
Servicing the Timing and 1 0.3-5
Slope Generators
TIME IN
mA
mA const
0.2
0.2
mA const
mA -
mA
2
0.2
=
=
0 mA, LO
12 mA)
U200 OUT
U220 OUT
U240 OUT
C DEL MODE J
U2 4 0 OUT
< DBL MODE )
U3 0 1
D I FFERENT IAL
OUTPUT
< DEL MODE )
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