Triggering Level - Tektronix 545A Instruction Manual

General Information
The
Tektronix
Type 545A
Oscilloscopes are
wide-range
general-purpose laboratory
instruments.
The Type
545A
provides accurate
measurements
in
the dc
to
30
me
range.
The
instrument
can be operated
with
any
Tektronix
letter-
series plug-in unit to satisfy
the requirements
for virtually
any application.
Special
circuits
incorporated
in
the
Type 545A
Oscilloscope
permit
an
accurate, continuously variable
delay
in
the
presentation of the
sweep
from
1
microsecond
to
10
sec-
onds
after
receipt of a triggering impulse. This feature
permits observation of
a
small portion of the
normal sweep,
accurate measurement of
waveform
jitter,
precise time
mea-
surements, as well as
many
other
uses.
Vertical-Deflection
System
All specifications for
the Vertical-Deflection
System
of the
Type 545A
Oscilloscope
depend upon
the plug-in unit
used
with the instrument.
The
following
specifications
are given
assuming
that
a
Type K
Plug-In Unit
is
used.
Type 545A:
Bandpass
DC
to
30
me
(3
db
down
at
30 me)
±V
2
db.
Risetime
0.012 microseconds
Triggering
Modes
TimeBase
A
—
Automatic,
AC, DC,
AC
Low
Frequency Re-
ject,
and High Frequency
Sync.
Time Base B
—
Automatic,
AC, and
DC.
Triggering Signal
Requirements
Internal triggering
—
a signal
producing
2 millimeters of
vertical deflection.
External triggering
—
a
signal of 0.2 volts to
10
volts.
Sweep
will
trigger
on
larger signals, but
TRIGGERING
LEVEL
control operates over a
±10
volt
range.
High Frequency
Sync.-
—
Assures a
stable display of sine
wave
signals to
approximately 30
me. Requires a signal producing
2 centimeters of vertical deflection or
an
external signal of
more
than 2
volts.
Sweep
Rates
Time Base
A
—
0.1
microseconds
to
5 seconds per centimeter
in
24 accurately calibrated
steps.
An
uncalibrated control
permits
sweep
rates to
be
varied continuously
between
0.1
microseconds
and
approximately 12 seconds per
centimter.
Calibrated
sweep
rates
are typically within 1%,
and
in
all
cases within 3%, of the indicated
sweep
rate.
Time Base
B
—
2
microseconds
to
1
second per centimeter
in
18 accurately calibrated
steps.
Sweep
rates
are typically
within
1%, and
in all
cases within 3%,
of
the indicated
sweep
rate.
Magnifier
Provides a 5-times magnification of the center 2-centimefer
portion of the oscilloscope display.
Extends
the
fastest
Time
Base
A
sweep
rate to 0.02
microseconds per centimeter
and
the
fastest
Time Base
B
sweep
rate to 0.4
microseconds
per
centimeter.
External Horizontal Input
Deflection factor
—
approximately
0.2 to
15
volts
per
centi-
meter, continuously variable.
Frequency response
—
from dc
to
240
kc.
Response
down
3
db
at
240
kc.
Horizontal input connector
characteristics
—
1
megohm
paral-
leled
by approximately 55
f.
Delayed
Sweep
Sweep
delay continuously variable
from
1
microsecond
to
10 seconds. Actual
delay
steps
(between
1.00
and
10.00)
are
within
1
%
of the indicated
delay from
2 p.
sec/cm
to
0.1
sec/cm;
within
3%
from
0.2
sec/cm
to
1
sec/cm.
Incre-
mental delay accuracy
is
within
0.2%.
Time
jitter
—
1
part
in
20,000.
Cathode-Ray Tube
Type
545A
Oscilloscope
—
Type T543P2.
Phosphors
—
Type
P2
phosphor normally
supplied; PI, P7,
and
Pll
phosphors
optional.
Other phosphors
available
on
spe-
cial
order.
Unblanking
—
dc coupled.
1-1