R805B
POSITION
B
sawtooth
from B
Sweep
Gen-
erator
A
sawtooth
from A
Sweep
Gen-
erator
External
horizontal
signal
from
B Trigger
Generator
R805A
LIBD
I
I
!
SW801B
I
MAG
I
Circuit
Description-Type
453/R453
SWJJO
I TRACE
FINDER'
I
I
I
I
I
I
I
I
I
I
I
Horizontal
deflection
signal to
horizontal
deflection
plates
Fig.
3-14.
Horizontal Amplifier
detailed
block
diagram.
In
the
EXT
HORIZ
pos1t1on,
the horizontal deflection signal
is
obtained from the Input Stage
of
the B Trigger Generator.
In
addition, this circuit contains the horizontal magnifier
circuit and the horizontal positioning network. Fig. 3-14
shows a detailed block diagram
of
the Horizontal Amplifier
circuit. A schematic
of
this circuit
is
shown
on
diagram
13
at
the rear
of
this manual.
Input Amplifiers
The
input signal for the Horizontal Amplifier
is
selected
by
the HORIZ
DISPLAY
switch,
SW801
A.
In
the A and A
INTEN DURING B positions
of
the HORIZ
DISPLAY
switch,
the sawtooth from the A Sweep Generator
is
connected to
the base
of
the - Input Amplifier, Q814, through
R803.
In
the
DELAYED
SWEEP
(B)
position, the B sawtooth
is
connected
to the base
of
Q814. Whichever sawtooth signal
is
con-
nected to the base
of
Q814 produces a current change which
is
amp:ified to produce a positive-going sawtooth voltage
at
the collector.
This
positive-going sawtooth signal
is
con-
nected to the base
of
Q834
in
the Paraphase Amplifier
stage.
In
the
EXT
HORIZ position
of
the HORIZ
DISPLAY
switch,
the external horizontal signal from the B Trigger Generator
®
circuit
is
connected to the base
of
the + Input Amplifier,
Q824, through
R821.
The
A and B sawtooth signals are
grounded
by
the HORIZ
DISPLAY
switch.
The
B
SOURCE
switch
selects
either the internal signal from Channel 1
(TRIGGER
switch
set
to
CH
1 ONLY)
or
an external signal
connected to the
EXT
HORIZ connector. When the internal
signal
is
selected, the Channel l deflection factor
as
indi-
cated by the
CH
l VOLTS/DIV switch applies
as
Horizontal
Volts/Division. More information
on
the external horizontal
circuitry
is
contained in the B Trigger Generator circuit
discussion.
Horizontal positioning
is
provided by the POSITION con-
trol,
R805A,
and the FINE control,
R805B,
connected to the
base
of
Q814.
These
controls vary the quiescent
DC
level
at
the base
of
Q814 which
in
turn
sets
the
DC
level
at
the
horizontal deflection plates to determine the horizontal
position
of
the trace.
C804-R804
eliminate common-mode
noise from the position controls.
Paraphase
Amplifier
The
output
of
the + and - Input Amplifier stages
is
connected to the Paraphase Amplifier stage, Q834 and Q844.
This
stage converts the single-ended input signal from either
3-21
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