Circuit
Description
—
Type
3B5
delayed,
magnified
sweep
as
controlled
by
the
Delay
and
Timing
Circuit.
The
Bright Baseline stage
allows
the
Sweep
Generator circuit
to
free-run
when
a
trigger signal
is
not
present for
auto
triggering.
Fig.
3-12
shows
a
logic
block
diagram
of
the
Sweep
Generator
circuit.
A diagram
of
this
circuit
is
shown
on
diagram
2
at
the
rear of this
manual.
Sweep
Gate
The
trigger
signal
at
the
output
of
the
Sweep Trigger
circuit
is
applied
to
the
Sweep
Gate
stage
through
T140.
Only
the
negative-going portions
of
the
trigger
signal
produce
a
voltage
across
the
primary
of
T140
because
D
142
reflects
a
minimum
impedance back to
the
primary
for
the
positive-going
portions.
This
produces
a
positive-going
trigger
pulse at
the
secondary of
T140.
Tunnel
diode
DI
45
is
quiescently
conducting
about
three
milliamps
of
current
which
is
not
enough
to
switch
it
to
its
high-voltage
state.
The
positive-going
trigger
pulse at the anode
of
D145
increases its
current and
it rapidly switches to the
high-
voltage
state where it
remains
until
reset
by
the
Sweep
Reset
Multivibrator
at
the
end
of
the sweep. The
positive-going
level
at
the
anode
of
D145
forward
biases
Q144
through
R145.
When
Q
1
44
comes
on,
its
collector
rapidly
goes
negative.
This
negative-going
step is coupled
to
the
output
emitter
follower
Q253
and
the
Disconnect
Emitter
Follower,
QI
53.
Emitter
Follower
Q253
provides
isolation
between
the
Sweep Gate stage
and
the
Unblanking
Driver
stage.
D254
clamps
the
emitter
of
Q253
so
it
does
not
go
more
than
about
0.5
volts
above
ground
level.
The
signal
at
the
emitter
of
Q253
is
coupled
to
the
base
of
the Unblanking
Driver
stage
through
R257
and
C257.
This
signal
is
also
coupled
to
terminal
4
of
the
interconnecting
plug, P21,
and
to
the
Seek
Circuit.
The
signal
to
terminal
4
of
P21
is
AC
coupled
by
C255
and
it
provides
the
alternate
trace
sync
pulse
for a
multi-trace amplifier
unit.
The
signal
to
the
Seek
Circuit
is
a
negative-going
sweep
gate
with
an
amplitude
of
about
—
6
volts. Duration
of
the
sweep
gate is
the
same
as
the
duration
of
the total
displayed
sweep.
Disconnect
Emitter
Follower
and
Diode
Q1
53
is quiescently
conducting
and
it
forward
biases
the
Disconnect
Diode,
D
155. With
D1
55
conducting,
current
from
the
Timing
Resistor
passes
through
the Disconnect
Diode
rather
than
charging
the
Timing
Capacitor.
The
negative
going
sweep gate
at
the
collector
of Q144
turns
the
Dis
connect
Emitter
Follower,
Q153,
off
and
reverse
biases
the
Disconnect
Diode.
Timing
current
through
the
Timing
Resistor
now
begins
to
charge
the
Timing
Capacitor
and
the
sweep
starts
to
run
up.
The
Disconnect
Diode
is
a
low-capacitance,
low-leakage,
fast
turn-off
diode
to
reduce
the switching time
and
improve
timing
linearity
at
the
start
of
the
sweep.
Sawtooth
Sweep
Generator,
Sweep
Output
Emitter
Follower
and
Timing
Capacitor and
Resistor
The
basic sweep
generator
circuit
is
a
Miller
Integrator.2
The
Sawtooth
Sweep Generator,
Sweep
Output
Emitter
2Pulse and
Digital
Circuits, Millman and Taub, McGraw-Hill, 1956,
P.214.
Follower
and
the
Timing
Capacitor
and
Resistor
stages
all
operate
together
to
produce
the sawtooth
for
horizontal
sweep.
When
the current
flow
through
the
Disconnect
Diode
is
interrupted
by
the
sweep
gate
signal,
the
Timing
Capaci
tor
begins
to
charge
through
the
Timing
Resistor.
The
Timing
Capacitor
and
Resistor are changed
for
the various
sweep
rates
listed
on
the
front
panel
(see
Delay
and Timing
Circuit
discussion).
In
the
0.1
μ
s
position,
variable
capacitor
C
16
8
is
the
Timing Capacitor.
This
capacitor
remains
in
the
circuit
at
all
sweep
rates
and is
paralleled
by
the
remaining
Timing
Capacitors
for
the
slower
sweep
rates.
The
charging
current
to
the
Timing
Capacitor
provided
by
the
Timing
Resistor
is
increased
10
times
or
100
times
to
provide
delayed
sweep
magnification
(see X10
and
X
1
00
Magnifier
Gates
dis
cussion).
As
the
Timing Capacitor
begins
to
charge
toward —
100
volts
through the Timing
Resistor,
the
grid
of
VI
63
goes
negative also.
This
produces
a
negative-going
change
at
the
cathode
of
V1
63
which
is
coupled
to
the
base
of
Q
161.
D
16
2
limits
the
reverse
voltage
across
the
Disconnect
Diode
to
protect
it
during warm
up.
Q161
amplifies
and
inverts
the
voltage
change
at
the
cathode
of V
1
63
to
produce
a
positive-going
signal
at
its collector.
D
1
65
clamps
the base
of
Q161
to
protect
it
during warm
up.
The
positive-going
change
at
the
collector
of
Q161
is
coupled
to
the
base
of
the
Sweep
Output
Emitter
Follower,
Q174.
D172
helps
turn
Q174
off
faster
during
sweep retrace.
The
voltage
level
at
the
emitter
of
Q
1
74
is
shifted six
volts
negative by zener
diode
D
1
73
to
provide
the
correct
output
DC
level
without
attenuating
the
signal.
The
positive-going
voltage
change at
the
anode
of
D
173
is
the
sweep
output
voltage.
This
voltage
is
also
connected
back
to
the
positive
side
of
the
Timing
Capacitor.
This
feedback
rises positive at
the same
rate
that
the
Timing
Capacitor
charges
negative.
Therefore,
the
Timing
Capacitor
appears
to
be
charging
toward
the
same
potential
at
all
times,
maintaining
a
constant
charge
rate
and
providing
a linear
sawtooth output voltage.
The
output
voltage
continues
to
rise
positive until the
circuit
is reset
through the
Sweep Reset
Multivibrator.
The
output
voltage
from
the
Sweep
Output
Emitter
Fol
lower
is
connected
to
the
Horizontal
Amplifier
to
produce
the
horizontal
CRT
deflection.
It
is also
connected
to
terminal
18
of
the
interconnecting
plug
through
R187
to
provide
a
sweep signal
current
to
the
amplifier
unit and
to
terminal
16
of
the
front-panel
PROGRAM
connector
through
R189
for
sweep output.
Sweep
Reset
Multivibrator
The
positive-going
sawtooth
voltage
at
the
emitter
of
Q1
74
is coupled
to
the
Sweep Reset
Multivibrator
through
R201
and
D228.
The
DC
level
of
the
positive-going
sweep
holds D228
reverse
biased
during
most
of
the
sweep time.
However,
when the
sweep
voltage
at
its
anode
rises
positive
enough
to
forward
bias
D228,
it
conducts
and
Q235
is
turned
off.
The
level
of
the
sawtooth
at
which D228
con
ducts
determines
the
sweep
length.
For
unmagnified
oper
ation,
X
1
(bar X
1
magnifier)
logic
from
the
Delayed
Sweep
Magnifier
Control
circuit
holds
the
cathode
of
D202
near
zero
volts
and
the
displayed sweep is
between
10.3
and
11.3
divisions long.
However,
for
either
X10
or X1
00
magnifier
operation,
the
X1
logic
level
is
about
—
12
volts
and
D203 is
reverse
biased.
The
cathode
of
D202
is
now
returned
to
—12.2
volts
through
R203.
This
lowers the
3-16
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...