Tektronix 7834

Theory of
Operation-7834
PIN 6
PIN 10
TRIGGER
PIN 5
CHARACTER
SCAN
PIN 16
Z-AXIS
LOGIC
OFF
COMMAND
PIN 14
VERTICAL
AND
HORIZONTAL
OFF
COMMAND
PIN 13
READOUT
INTENSITY
PIN 12
0V
0V
_0V
0V
0V
-+6
V
CHARACTER
SCAN
PIN
16
Z-AXIS LOGIC
OFF COMMAND
PIN 14
VERTICAL AND
HORIZONTAL
OFF
COMMAND
PIN
13
READOUT
INTENSITY
PIN 12
, +6V
NOTE
: TEST OSCILLOSCOPE EXTERNALLY TRIGGERED
FROM TP3450
(1195-30) 1988-56
0V
0V
Figure 3-31 . Detail of
output at pins 12, 13, 14 and 16 of U2126 .
It also produces
the Strobe pulse through Q3442 and
CR3442 to signal other stages within the Readout System
to begin the sequence necessary to
produce
a
character . The
collector level of Q3442 is also
connected
to
Symbol
Character Generator, U3463, through
CR3443 . This acti-
vates U3463 during the quiescent period of
the Strobe pulse
(collector of Q3442 negative)
and diverts the output current
of Row Decoder U3429 to
row 2 . The purpose of this
configuration is to
prevent the Zeros Logic and Memory
stage U3401
from storing incorrect data during the quies-
cent period of the Strobe
pulse
.
When the Strobe pulse goes
positive, CR3443 is
reverse-biased to disconnect Q3442
from
U3463 and
allow the Row Decoder to operate in the
normal manner .
The next signal to be produced is the X-Y Inhibit command
at
pin 13 . This positive-going signal disconnects the plug-in
NOTE : "TEST OSCILLOSCOPE EXTERNALLY TRIGGERED
signals from the vertical and horizontal deflection systems .
FROM TP3450

(1195-29) 1988-55

The Ready signal derived from this output is connected to
the Decimal Point and Character Position Center stage
and
Figure 3-30 . Output waveforms of the
Timer stage .

the Format Generator stage .