Tektronix 453 User Manual

B SWEEP GENERATOR
General
The B Sweep Generator circuit is basically the same as
the A Sweep Generator circuit. Only the differences be-
tween the two circuits are discusssd here.
The following
circuits operate as described for the A Sweep Generator
(corresponding circuit numbers assigned
in the 700-799
range): Sweep Gate
(D705, Q704), Disconnect Diode (D742),
Sawtooth Sweep Generator (Q743 and Q741), Sweep Reset
Emitter Follower (Q753) and the Sweep Start Amplifier
(Q754). Fig. 3-13 shows a detailed block diagram of the B
Sweep Generator circuit. A schematic of
this circuit is shown
on diagram
11 at the rear of this manual.
Output Signal Amplifier
Basically, the B Output Signal Amplifier is the same as
the corresponding circuit
in the A Sweep Generator circuit.
Two unblanking gates are available from the collector of
Q714.
An unblanking gate is connected to the Z Axis Amp-
A sweep
from
A Sweep
Generator
Trigger pulse
from
B Trigger
Generator
Delay-Pickoff
Comparator
Q764, Q769,
D764
DELAY-TIME
MULTIPLIER
Delay Multi-
vibrator
Q768, Q772
SW801A
[H°"oRIZ DISPLAY k,
I B SWEEP MODE~ .................
SW635 ',
Sweep Reset
Multivibrator
Q775, Q785
Sweep Gate
D705, Q704
Circuit Description-Type 453/R453
lifier circuit through R717 and the HORIZ DISPLAY switch
to unblank the CRT to display the B sweep. For A INTEN
DURING B operation, additional unblanking current is added
to the A unblanking gate during the B sweep time. This
produces a display which is partially unblanked during A
sweep
time and further unblanked during B sweep time· to
produce a display which has an intensified portion coinci-
dent
with the B sweep time.
Delay-Pickoff Comparator
The Delay-Pickoff Comparator stage allows se·lection of
the amount of delay
from the start of the A sweep before
the B Sweep Generator
is turned on. This stage allows the
start of B sweep to be delayed between 0.20 and 10.20
times
the setting of the A TIME/DIV switch. Then, the B Sweep
Generator
is turned on and operates at a sweep rate inde-
pendent of the A Sweep Generator (determined
by setting of
B
TIME/DIV switch).
Q764A and B are connected as a voltage comparator.
In this configuration, the transistor with the most positive
SW530B
B TIME/DIV I
...... _
Disconnect
Diode
D742
--
Sawtooth
Sweep
Generator
Q743, Q741
B sweep to
Horizontal
Amplifier
~
B TIME/DIV
'-R
7
-
4
-
0
-y- VARIABLE
>------......~ B ends A pulse
SW555
B ENDS A
to A Sweep Generator
B unblanking
gate to
r">-----------__..__... Z Axis Amplifier
A intensified
unblanking gate
to Z Axis
Amplifier
~ l,......B_G_A-TE-1
Fig. 3-13. B Sweep Generator detailed block diagram.
3-19

Tektronix 453 Specifications

General

Brand	Tektronix
Model	453
Category	Test Equipment
Language	English