Tektronix T922 User Manual

Circuit Description-T921/T922/T922R
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X .1
T922R
SINGLESWEEP, OUTPUT BUFFER,& Z AXIS
Diagrams 7, 8, and 9, and associated circuit descriptions, pertain to circuitry that is used only in the T922R and is not
present in the T921 and T922 bench versions . For circuit descriptions and diagrams of circuitry common to the T921, T922, and
T922R, refer to diagrams 1 through 6 .
SINGLE SWEEP
To
operate in the Single
Sweep mode, S2400B is set to SINGLE
SWEEP . This applies
the signal from
U2402B
to pin 2 of U2156A
(see diagram 5) via P2412 pin
3 .
Pin
8 of U2402B now controls the
ability of the Trigger Generator to supply a trigger
signal to the
Sweep Generator . Fig . 7-3 shows a timing diagram of the signals
generated during a single sweep display .
The sequence of events during a single-sweep
display is as
follows :
1
. S2400B is in the SINGLE SWEEP position . Before time A
(see
Fig .
7-3)
pin
8 of U2402B is HI clamping pin 2 of U2156A HI .
2 . At time A the RESET button (S2400A) is pushed
and
released . Pin 4 of U2402A is momentarily grounded and pin 1 of
U2402A is momentarily ungrounded . This sets, then resets
U2402A,which
provides a bounce-free pulse at pin 5 of U2402A .
3 . The pulse from pin 5 of U2402A
is
connected
to
the
clock
input of U2402B, pin 11 . This causes pin 9 of U2402B to go HI,
lighting the READY indicator, CR2400 . At the same time, pin 8 of
U2402B goes LO, reverse biasing CR2406 . With CR2406 reverse
biased, pin 2 of U2456A is released .
4 . At time B the Trigger
Generator produces a trigger signal
causing the
sweep gate, at
pin
3 of U2234A (see diagram 6), to
step LO . This causes the Sweep Generator
to begin
the
sweep
ramp .
5 .
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The sweep gate signal from pin 3 of U2234 is applied to pin
13 of U2402B via P2412-1 . At time B, the
sweep gate steps LO .
This resets UP-402B . Pin 9 of U2402B steps LO, which ex-
tinguishes the READY indicator CR2400 . At the same time, pin 8
of U2402B steps HI, which forward biases CR2406, forcing pin 2
of U2156A
HI
.
While
pin 2 of U2156A is held HI, the Trigger
Generator is locked out and cannot supply another trigger signal
to the Sweep Generator .
No furthersweepscan be displayed until
the RESET button is again
pushed to repeat the cycle .
02432 is a unity-gain
common-emitter amplifier . P2430 may
be installed on J2430 in either of two positions
.
In
one position
(index at + = BRIGHT), 02432 is inserted in the external Z
axis
signal path from the rear-panel Z AXIS IN connector J2430, and
inverts the signal, allowing a negative-going applied signal to
decrease the crt intensity (and positive-going signal to increase
REV . A, JUNE 1976
Z
AXIS INVERTER
intensity) . In the other position of P2430 (index at + = DIM),
02432 is bypassed, allowing a positive-going applied signal to
decrease the crt intensity (and negative-going signal to increase
intensity) .
SWEEPGATE OUT AMPLIFIER
The
Sweep Gate signal is picked
off pin
3 of U2234 (see
diagram 6) and is applied via P2412-1 to the inverting amplifier,
02422 . This circuit inverts the Sweep Gate signal and provides
isolation between the output connector and the Sweep
Generator .
INPUT
SIGNAL
RANDOM
PULSES
PIN 1
U2402A
PIN 4
U2402A
PIN 5
U2402A
AND
PIN 11
U2402B
SWEEP
RAMP
COLLECTOR OF
02246
SWEEP
TRIGGERS
SWEEP ENDS
HOLDOFFSTARTS
1982-62
Fig . 7-3 . Timing diagram of signals generated during a single-
sweep display .
PIN 9
U2402B
READY LAMP
PIN
8
U2402B
SWEEP
DISABLE
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PIN 2
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U2156B
TRIGGER
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PIN 3
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U2234 j
SWEEP
GATE
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A B
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Tektronix T922 Specifications

General

Brand	Tektronix
Model	T922
Category	Test Equipment
Language	English