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Schmitt output D214-11 and NAND gate input D211-3 are a t level H when the hold-off capacitors are dis-
charged. The H level on output pin 6 of flip-flop D212 is routed via 021 1 (3,4,5,6) and D209 (2,3,1) t o
M A I N S W E E P
H O L D O F F SWEEP
D212 11
D 212 16
D 2 0 9 1 3
TRIGGER P U L S E S
0212 19
AUTO
MTB trigger pulses are applied as a current signal t o the CURRENT-VOLTAGE CONVERTER. If a trigger
pulse occurs in this mode, transistors V291 and V292 convert the selected trigger source current signal into a
voltage signal, and emitter-follower V293 makes D214-4 input logic L. This trigger pulse is applied a t H level
t o clock input pin 11 of flip-flop D212, which switches over t o make output pin 9 logic
during the hold-off period because 0214-5 i s L, or reset input D212-13 i s L.
The
t o start the time-base.
As described for the free-run mode, the end of the time-base sweep is detected and the hold-off time-base is
started.
When this occurs, output pin 6
L and the time-base is switched off. Moreover, the one-shot multivibrator D213 i s triggered and output D213-6
stays a t level L for 100 ms after the H to L transition of the clock input on pin 1.
If D213-6 is L, then D211-5 is also L. This means that it i s not possible to start the time-base
hold-off period via the path D211 (3,4,5,6) and D209 (2,3,1). Now the MTB can only be started if a trigger
pulse appears. An incoming trigger pulse is applied t o the clock input (1 1) of flip-flp D212 t o make output pin
MTB starts.
V O L T A G E
W A V E F O R M S
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F R E E R U N - 1
2.5.
Important voltage waveforms in the
mode with trigger pulses
H
level from
of
D209 (8,9,10) to the reset input (13) of flip-flop D212. As
gate
H .
This H level is applied t o pin 11 of NOR gate D209, which makes output pin 13 a logic
I N
S W E E P GATING
L O G I C .
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+ A U T O
W I T H TRIGGERS-
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MTB
control logic
flip-flop D212 becomes L. This L level is routed via NAND
. . ..
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M A T 912
H .
This cannot occur
via NOR gate
D209 (1 1.12.13)
D211
gate
a result, output pin
a t the end of the
and the
2-19
9 does
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