Tektronix 7613 User Manual

Vertical Amplifier
Auxiliary Y-Axis Input Amplifier
The Auxiliary Y-Axis Input Amplifier accepts an input
from horizontal plug-in units having compatible features.
Normally, this input is a positioning voltage to offset the
display. The single-ended signal connected to the input of
this stage is converted to a push-pull signal at the collectors
of Q2365 A and B. This signal is connected to the
Delay-Line Buffer stage along with the output from the
Vertical Channel Switch.
Delay-Line Buffer
The output of the Vertical Channel Switch stage, along
with any signal from the Auxiliary Y Axis input Amplifier,
is connected to the bases of Q2386 and 02396. These
transistors are connected in a common emitter shunt
feedback configuration to provide a low impedance sum-
ming point, and voltage gain. L2386-L2396, C2387-R2387
and C€2397-R2397 provide high-frequency peaking and
reverse termination for the Delay Line.
Delay Line
Delay Line DL2400 provides approximately 150 nano-
seconds delay for the vertical signal, to allow the horizontal
circuits time to initiate a sweep before the vertical signal
reaches the vertical deflection piates 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 about 50 ohms per side, or
about 100 ohms differentially. It is of the coaxial type,
which does not produce preshoot or phase distortion in the
CRT display.
VERTICAL AMPLIFIER
General
The Vertical Amplifier circuit provides final armplifica-
tion for the vertical signal before it is applied to the vertical
deflection plates of the CRT. This circuit includes an input
from the BEAM FINDER switch to compress an over-
scanned display within the viewing area of the CRT. Fig.
3-18A shows a detailed block diagram of the Vertical
Amplifier circuit. A schematic of this circuit is shown on
the diagrarn accompanying this insert.
M20610/1073
7613/R7613 SN B150000-up
Centering and Readout Amplifier
02530-02430 compose a paraphase amplifier to provide
balance or centering control for the vertical amplifier by
changing the ratio of the current that is summed at the
emitters of Q2441-Q2541. In addition this stage provides
the input for the vertical readout signal through J2534 and
the base of Q2530.
Input Amplifier
Forward termination of the delay line is accomplished
by R2402-R 2501, in conjunction with the input impedance
of Q2405-02505. R2402-R2501 also act as load resistors
for the Delay Line Buffer stage. Q2405-02441-02505-
Q2541 are connected in a cascode configuration. The RC
networks in the emitters of Q2405-02505 compensate for
the losses in the delay line and provide some temperature
compensation for the vertical amplifier.
Thermal balancing of the vertical amplifier is accom-
plished by adjusting the base voltage of Q2441-02541.
The signal from 02441-02541 is connected to the
output amplifier through the transmission line, which is
terminated by L2448-L2548 and R2448-R2548. The
Vertical Gain is adjusted by loading the collectors of
02441-02541 with R2446,
Beam Finder Network
The Beam Finder Network provides a means of locating
a display that overscans the graticule area. Under normal
operation, the Display Limit Command is at —15 volts,
which holds Q2427 cut off and allows Display Limit
Current for the Horizontal Amplifier to rise to about +15
volts. During this time, Q2423 is held on and emitter
current from 02405-02505 flows through Q2423 to
ground. When the Beam Finder switch is pressed, the
Display Limit Command rises positive, turning Q2427 on
and 02423 off. This pulls the Display Limit Current to —15
volts, and reduces the emitter current of 02405-02505 to a
Page 5 of 13
7613

Tektronix 7613 Specifications

General

Brand	Tektronix
Model	7613
Category	Test Equipment
Language	English