Wavetek 145 Instruction Manual page 27

waveform with the front panel function switch. This output,
a normal pulse or a complemented pulse, is routed to the
square wave shaper and output, if selected, through the
output amplifier as a variable amplitude pulse. The pulse
modes of normal, delayed and double are shown as timing
diagrams in figures 4-4, 4-5 and 4-6.
4.5 WIDTH AND DELAY ONE-SHOTS
The pulse width and delay one-shots feature front panel
adjustable current sources to regulate the capacitor charge
time and as a result, the one-shot pulse width. The steady
state condition of the one-shot circuit is as shown in figure
4-7: Upon triggering,
Q
goes low, the switch transistor
switches off and the capacitor begins to charge. When the
voltage across the capacitor is sufficient, the level detector
senses the set level, the flip-flop is cleared and the circuit
reverts to its steady state condition. The duty cycle of the one-
shots is limited by the capacitor discharge time when return-
ing to steady state conditions.
HYSTERESIS
. . . - - - - - - - - - - - - - - - - - - - - - - - - - - - 4
SWITCH
i - - - - - - l -
©
I+
I-
TRIGGER
COMPEN-
SATION
!
I+
TRIGGER
®
0
®
~
CR26
©
®
SYNC
(P1-1)
NOUTPUT
I
- -
-
-
-
©I
TRIGGER TRIGGER
CONTROL SQUARING
LOGIC
©
CIRCUIT
7
ITRIG
IN
I i
I
L
_2RIGGER/PULS~ BOARE._
_J
TRIGGER
~ ~ ✓ LEVEL
:::::;,: ~
+ ' . - - - - - - - - - - - ,
o_J
®·®
+
©
@
+
®
+7
0 :
®
+
Figure 4-3. Tri'gger Circuit and Timing
4-3