SECTION
3
CIRCUIT
DESCRIPTION
Introduction
This
section
of
the
manual
contains
an
electrical
descrip
tion
of
the
circuitry
used
in
the
Type
3B5
Automatic/Pro-
grammable
Time
Base
unit.
This section
begins
with
a
basic
block-diagram
discussion
of
the
instrument
using
the
simplified
block
diagram
shown
in
Fig.
3-1.
Then,
a
logic
discussion
explains
which
blocks
operate
in
each
of
the
three modes
of
operation;
Manual
Mode,
Seek
Mode
and
External
Mode.
In
the
detailed
Circuit
Description,
a
logic
block
diagram
shows
the
interconnections
between
the
stages
in
each
major
circuit
and
the
input
and
output
signals.
Also
shown
is
the
relationship
of
the
front-panel
controls
to
the
individual
circuits.
A
complete block
diagram is
located
in
the
Dia
grams
section
at
the
rear of
this
manual.
This
block
diagram
shows
the
overall
relationship
between
all
circuits in
this
instrument.
Complete
schematic diagrams of
each
circuit
are
also
given
in
the
Diagrams
section.
Refer
to
these
dia
gram
throughout
the
following
circuit
description for
elec
trical
values
and
relationship.
BLOCK
DIAGRAM
DISCUSSION
A
simplified block diagram
of
the
Type
3B5
is
shown
in
Fig.
3-1.
Only
the
basic interconnections
between
the
indi
vidual
blocks are
shown
on this diagram. Each
block
in
this
block
diagram
represents
a
major
circuit
within
the
instru
ment.
The
number
on
each
block
refers to
the
circuit
diagram
at
the
rear
of
this
manual
which shows
the
complete
circuit.
The
Sweep
Trigger
circuit
produces
an
output
pulse
which
turns
on
the
Sweep
Generator
circuit
to
produce
the
sweep
signal.
The
output
pulse
from
the
Sweep Trigger
circuit
is
derived
from
the
input
trigger
signal.
The
input
signal
can
be
either
an
internal signal from
the
amplifier
unit, which
is
a
sample
of
the
vertical
deflection
signal,
or
an
external
signal
applied
to
the
EXT
TRIG
INPUT
connector.
Trigger
slope,
level,
mode,
coupling
and
source
are
externally
pro
grammable
in
the External Mode
of
operation
(EXT).
For
Seek
Mode
operation
(SEEK)
a
control signal
from
the
Seek
Circuit
allows
the
Sweep
Trigger circuit
to
switch
to
auto
triggering
if
the
front-panel
controls
are
incorrectly
set
or
the
correct
trigger signal
is
not
applied.
The
Sweep
Generator
produces
a
linear
sawtooth
signal
when
triggered by the
Sweep
Trigger
circuit.
The
slope
of
the
sawtooth
produced
by
the
Sweep Generator circuit
is
controlled
by
the
Delay
and
Timing
Circuit.
The
output
of
the
Sweep Generator
is
amplified
by
the
Horizontal
Ampli
fier
to
produce the
horizontal
deflection for
the indicator
oscilloscope
CRT.
Other
signals
for
horizontal
deflection
can
also
be
applied
to
the
Horizontal
Amplifier
through
the
PROGRAM
connector.
The
horizontal
position
of
the
trace
can
be
externally
programmed in
the
External
Mode
of
operation.
The
Delay
and Timing
Circuit
provides
delayed
sweep
magnification
in
addition
to
selecting
the
basic
sweep rate.
The
sweep
rate
is
controlled
by
the
MANUAL
TIME/DIV
switch
for
Manual
Mode
operation
or by
the
Counter
Circuit
for
Seek
and
External
Mode
operation.
The
amount
of
delay
before
sweep magnification
begins
is
controlled
by
the
front-panel
multi-turn DELAY
control for
Manual
and
Seek
Mode
operation,
or is
externally
programmed
in
the
External
Mode
of
operation.
The
Delayed
Sweep
Magnifier
Control
circuit
determines
the
magnification
ratio
and
also
provides
a
correct
readout
on
the
readout
panel.
The
magnification
ratio
(X
1
,
X10,
X100)
is
selected by
the
front-panel
DLY'D
SWP
MAG
switch
for
Manual
and
Seek
Mode
operation
or
it
is
externally
programmed
for
External
Mode
operation.
In
the
Seek
Mode
of
operation,
the
Seek
Circuit
produces
output
pulses
which
allow
the
Counter
Circuit
to
select
the
proper
sweep
rate
for a
two
to six
cycle
display (nominal
CYCLES/SWEEP
adjustment).
The
Counter
Circuit
can
also
be
externally
programmed
to
select
the
sweep
rate
in
the
External
Mode.
The
Readout
Logic
circuit
decodes
the
sweep
rate
control
logic
levels
from
the
Counter
Circuit
and
the
magnification
logic
level
from
the
Delayed
Sweep
Magnifier
Control
circuit
to
provide
the
correct
readout panel
display
in
the Seek
and
External
Modes
of
operation.
For
Manual
Mode
operation,
the
sweep
rate
and
readout-panel
display
are
determined
by
the
MANUAL
TIME/DIV
switch
and
the
DLY'D
SWP
MAG
switch
located
in
the
Readout Logic
circuit.
The
Readout Board
provides
the
front-panel
readout
of
instrument
operation.
The
bulbs
which
produce
the
readout
are controlled
by
the
Sweep
Generator,
Delay
and
Timing
Circuit
and
the
Readout Logic
circuit.
The
operating
mode of
the
instrument
is
controlled
by the
Operating
Mode
Power
circuit. This
circuit
produces
output
voltages
to
control
those
circuits
associated
with
the
Manual
Mode, Seek
Mode
or
External
Mode
functions.
External
Mode
operation
can
be
selected
by
external
program
and
it
has
priority
over
the
other
modes.
The
Seek
Mode can
be
selected
(when
not in
the
External
Mode)
by
a
seek
com
mand from
the
front-panel
SEEK button,
remote
seek
com
mand from
the
amplifier
unit
or
remote
seek
command
through
the front-panel PROGRAM
connector.
The
Manual
Mode
is
obtained (except
when in
External
Mode)
when
the
unit
is
first turned
on,
when
the MAN
button
is
pressed,
when
the
MANUAL
TIME
/DIV
switch
setting
is
changed or when
the
external
program
is
removed.
The
Voltage
Distribution
circuit
provides
the
power
supply
voltages
from
the
indicator
oscilloscope
to
all
of
the circuits
within
this
unit.
This
circuit
contains
the
decoupling
networks
to
provide
the
decoupled
voltages
used throughout
this
unit.
LOGIC
DISCUSSION
Manual
Mode
Operation
Fig.
3-2
shows the
circuits
in
the
Type
3B5
which
are
operative in
the
Manual
Mode.
In
this
mode
of
operation,
the
unit
operates
as
a
conventional
time
base
with
operation
determined
by
the
front-panel
controls.
The
Operating
Mode
Power
circuit
applies
a
control
level
to
the
other
circuits
to
either
lock
out
the
Seek
and
External
Mode
func
tions
or
to
activate
Manual
Mode
functions.
The
MANUAL
3-1
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...