Tektronix 7834 User Manual

VERTICAL
SIGNAL
FROM
VERTICAL
INTERFACE
X-Y
INHIBIT
FROM
READOUT
SYSTEM
AUXILIARY
Y-AXIS
SIGNAL
FROM
MAIN
INTERFACE
Y-READOUT
SIGNAL
FROM
READOUT
SYSTEM
Delay Line
High-Frequency Amplifier
AUXILIARY
INPUT
AMPLIFIER
01634,
01700
01624,
01720
01694,
01710
Delay Line DL650 provides approximately
65 nanoseconds
of delay (for the vertical signal) to
allow the horizontal
circuits time to initiate a sweep
before the vertical signal
reaches the vertical deflection
plates of the crt . This allows
the instrument to display
the leading edge of the signal
originating the trigger
pulse when using internal triggering .
The delay line
used in this instrument has a characteristic
impedance of 100 ohms differentially . It is of the coaxial
type that does not produce preshoot or
phase distortion in
the crt display .
The
High-Frequency Amplifier stage, consisting primarily
of integrated
circuit
U1685,
provides a 50 ohm input
impedance (100 ohms
differentially) for the Vertical Amp-
lifier circuit to
permit accurate delay-line termination . The
components connecting
the input signal to U 1685 provide
forward
termination and compensation for the delay
line .
Components R1658 and C1658 provide adjustable
high-
frequency compensation . Resistors R 1688 and R 1682 set
the quiescent
operating level of U1685 while R1683
and
R 1687 are selected to accurately set the gain of the stage
.
Resistors R1683 and R1687 connected to
pins 6 and 12
provide a signal path for the output of the
Auxiliary Y-Axis
Amplifier stage . The Vert Gain adjustment R1730
sets the
Figure 3-43 . Detailed block diagram of
the Vertical Amplifier circuit .
Auxiliary Input Amplifier
Theory of Operation-7834
VERTICAL
SIGNAL
TO
BEAM 2
VERTICAL
DEFLECTION
PLATES
OF CRT
(1676-94) 1988-68
resistance
between the output terminals of
U1685 to con-
trol
the current gain of this stage . This adjustment
sets the
overall gain of the Vertical Amplifier circuit .
Thermistor
T1731
compensates for gain change with
temperature
changes .
The Auxiliary Input
Amplifier controls the bias current to
the High-Frequency
Amplifier stage to provide centering
for the overall Vertical
Amplifier circuit . This stage
also
provides
readout and auxiliary inputs to the
Vertical Amp-
lifier . The auxiliary Y-Axis signal originates
from dual time-
base units with alternate sweep switching
and vertical
positioning . This signal is amplified by 01624
and applied
to
01720 through diodes CR1690, CR1696
and CR1697 .
Transistors 01720 and 01710 form a
paraphase amplifier
to convert the single-ended input
signal to a push-pull
signal which is coupled to
the bias inputs of U1685 .
The X/Y Inhibit
signal and Y-Readout signals are developed
by the Readout
System . When readout is displayed, the
X-Y inhibit signal goes
HI
at
J1738 and turns 01694 on .
The collector of 01694
drops which reverse biases CR 1690
(blocking auxiliary
Y-Axis signal) and turns 01700 on
providing readout centering current, adjustable by
R1700 .
The Y-Readout
signal at J1799 is coupled to the base of
01720 through R1635
.
3- 5 9

Tektronix 7834 Specifications

General

Brand	Tektronix
Model	7834
Category	Test Equipment
Language	English