Circuit
Description
—Type 3B5
CRT
for horizontal
deflection.
This
circuit
contains
the
hori
zontal
positioning
network
and
an adjustment
to
calibrate
the
horizontal
gain
of
this
unit
to
the deflection
sensitivity
of
the
indicator
oscilloscope.
An
external
horizontal
deflec
tion
signal
can
be applied
to
the
circuit
through
terminal 4
of
J30
and
an
external
horizontal
position
level
through
terminal
14
of
J30.
A
X10
gain
network
is
connected
to
the
base
circuit
of
the
Input
Amplifier
to
provide
the correct
sweep
rate
for
the
10
ns
timing
decade
(i).
Fig.
3-17
shows
a
logic
block
diagram
of
the
Horizontal
Amplifier.
A
dia
gram
of
this
cirucit
is
shown
on
diagram
4
at
the rear
of
this
manual.
Input
Amplifier
The
Input
Amplifier,
Q514,
is
a
feedback (operational)
amplifier
to
provide
stable
gain
and
low
input
impedance.
The
HORIZ
GAIN
adjustment,
R515,
in
the
feedback
loop
controls
the
amount
of
feedback
from
the collector
to
the
base,
thereby
setting
the
overall
gain
of
the
stage.
The
input
impedance
of
the
Input
Amplifier
is
low
and
it
is a
current-driven
amplifier.
For
normal
operation,
the
base
of
Q514
is
driven
from
three
current
sources:
1)
The
sawtooth
voltage
applied
through
R501-R502-C502
produces
a
cor
responding
sawtooth
current
at
the
base
of Q514; 2)
A
quies
cent bias
current
is
applied
to
the
base
of
Q514
through
R523
and
R529;
3)
The
horizontal
POSITION control
adds
or removes
current
at
the
base
of
Q514.
For
the
10
ns
timing decade,
10
ns
(i)
decade
logic ener
gizes
K512. K512-1
connects
the network
C507-R507-R508-
R509 in
parallel with
C502-R502
to
provide
10
times
more
sawtooth
current to
Q514.
This
produces
an
output
sawtooth
which
rises
10
times
faster
to
provide
the
desired
10
times
gain
increase
for
the 10
ns
timing
decade.
R505
adds
a
posi
tioning
current
to
the
base
circuit
for
registration
in
the
10
ns
timing decade.
This
added current allows
the
trace
to
start
at
the
same
point
on
the
graticule
when
switching
from
0.1
microseconds/division
to 50
nanoseconds/division.
For
the
10
nanosecond
and
20
nanosecond
sweep rates,
an
addi
tional
positioning
current is added by
the —
12-volt
level
on
either
the
"1"
or “
2"
logic line.
The
Horizontal
Amplifier
may
be used to
provide
hori
zontal deflection
from
sources
other
than
the
internal
sweep
generator
by applying the
horizontal
deflection
signal
to
terminal
4
of
J30.
The
Sweep Generator
must
be
disabled
by
applying
a-
lockout
signal
through
terminal
7 of J30.
An
unblanking
voltage
is
also
necessary
at
terminal
13
of
J30.
See
External Horizontal
Deflection
in
Section
2
for
complete
operating
information.
For
External Mode operation,
the
horizontal position
of
the
display
can
be
externally
controlled
through
terminal
14
of
J30.
In
this
mode,
—
12.2
volts
External
Power
is
applied
to
the
anode
of
D526
to
reverse-bias
it.
Then, the
current
through
R528,
which
normally
flows
through D526
and
R525,
is
connected
through
D528
and
R523
to
establish
a
negative
bias
level
at
the
base
of Q514.
By
adding
cur
rent
through
terminal
14,
the
desired
external
program
hori
zontal
position can
be
established.
Notice
that
the
front
panel
POSITION
control
is
not
disconnected
for
External
Mode
operation.
The
external
program
position
level
oper
ates as
a
vernier
for
the
front-panel
POSITION
control.
Left
Output
Amplifier
Q534,
Q543 and V544
are
connected
as
a
feedback
ampli
fier
for
gain
stabilization and
linear
output
to
the CRT
deflection
plates.
The
output
signal
at
the
plate
of
V544
is
in
phase
with
the
negative-going signal
applied
to
the
base of
Q534.
Negative
feedback
is
provided
from
the
plate
of
V544
to
the
emitter
of
Q534
through
R546
and
C546.
Diodes
D531
and
D532
connected
between
the
emitter
and
collector
of
Q534
protect
this
transistor
from excess
input
voltage.
In
addition,
they
improve
the
recovery time
of
Q534 when
driven
by
a
large
signal,
particularly
for
mag
nified
operation at
fast
sweep
rates.
The
negative-going
deflection signal
at
the
plate
of V544
is
connected
to
the
left
CRT
deflection
plate
through
terminal 17
of P21.
Right
Output
Amplifier
The
Right
Output
Amplifier
is
basically
the
same
as
the
Left
Output
Amplifier except that it
produces
an output
signal
180°
out
of
phase
with
the
input
signal.
The
negative
going
signal
at
the
collector
of Q514 is connected
to
the
base
of
Q553
through
the
compensated
voltage
divider
C551-
R551-R552.
C551
provides
high-frequency
compensation
for
the
Horizontal
Amplifier. Q553,
Q554,
V564A
and
V564B
are
connected
as
a
feedback amplifier.
Negative
feedback
is
provided
from
the
cathode
of
V564B
to the base
of
Q553
through
R567
and
C567.
The
input
signal
is
inverted
through
Q553-Q554
but
is
not
inverted
through
the
remainder
of the
circuit
to
produce a
positive-going
output
signal.
This
posi
tive-going
deflection signal
is
connected
to
the
right
CRT
deflection
plate
through terminal
21
of
P21
Readout
Logic
General
The
Readout
Logic circuit
determines
the decade and
multiplier
readout
on
the front
panel
of
the
unit.
For
manual
operation,
the
MANUAL
TIME/DIV
and
DLY'D
SWP
MAG
switches
determine
the
logic
to
control
the
readout
panel.
For
Seek
or
External
Mode
operation,
the
readout
is con
trolled
by
the decade,
multiplier
and
magnifier
logic
applied
from
the
Counter
Circuit
and
the
Delayed
Sweep
Magnifier
Control
circuit.
The
decade
logic
and
multiplier
logic
is
distributed
from this
circuit
to
the
Sweep Generator,
Delay
and
Timing
Circuit
and
the
Horizontal
Amplifier
circuits.
Fig. 3-18 shows
a
logic
block diagram
of
the
Readout
Logic
circuit.
A
diagram
of
this
circuit
is
shown
on
diagram
5
at
the
rear
of
this
manual.
Multiplier
and
Decade
Readout
The
Multiplier
and
Decade
Readout stages
provide
the
front-panel
readout
of
the sweep
rate. These
stages
are
controlled
by
the
Manual
Readout Decoding
stage
for
Manual
Mode
operation
or
the
decade
and
multiplier
logic
from
the
Counter
Circuit
for
Seek
and
External
Mode
Operation.
Manual
Readout
Decoding
The
MANUAL
TIME/DIV
switch,
SW450,
and
the
DLY'D
SWP
MAG
switch,
SW940, determine
the readout
panel
3-27
Содержание 3B5
Страница 4: ...Fig 1 1 Type 3B5 Automatic Programmable Time Base unit Type 3B5...
Страница 15: ...Operating Instructions Type 3B5 TYPE 3B5 CONTROL SET UP CHART Fig 2 2 Control set up chart 2 7...
Страница 48: ...CO I o Fig 3 13 Delay and Timing Circuit logic block diagram Circuit Description Type 3B5...
Страница 61: ...GO i GO GO Fig 3 22 Seek Ciicuit Logic block diagram Circuit Description Type 3B5...
Страница 70: ...u k KJ Fig 3 29 Circuit conditions for Manual Mode operation Circuit Description Type 3B5...
Страница 71: ...w K w Fig 3 30 Circuit conditions for Seek Mode operation Circuit Description Type 3B5...
Страница 72: ...w I u U Fig 3 31 Circuit condition for External Mode operation Circuit Description Type 3B5...
Страница 88: ...Maintenance Type 3B5 Fig 4 9 Location of components on Logic Card 4 14...
Страница 89: ...u Oi Fig 4 10 Location of components on Counter Card Maintenance Type 3B5...
Страница 92: ...NOTES I...
Страница 104: ...NOTES...
Страница 106: ...Calibration Type 3B5 Fig 6 1 Recommended calibration equipment...
Страница 160: ......
Страница 176: ...J400 RtADOUT BOARD 3B5 PLUG IN A READOUT...
Страница 182: ...397 R E A D O U T B O A R D 10 6b READOUT BOARD...
Страница 184: ...FIG 1 FRONT SWITCHES TYPE 3B5 AUTOMATIC PROGRAMMABLE TIME BASE...
Страница 185: ...FIG 2 CHASSIS REAR 3 GS to TYPE 3B5 AUTOMATIC PROGRAMMABLE TIME BASE...
Страница 186: ...OPTIONAL ACCESSORIES...