Variable Hold Off; Mainframe Operating Modes; Applications; Time-Interval Measurements - Tektronix 7B10 Instruction Manual

Operating Instructions— 7B 10
Operators
SWEEP
MAGNIFICATION
The sweep
magnifier can be used
to
expand
the display
be
a factor of 10.
The
center
division of the unmagnified
display
is
the portion
visible
on
the
crt in
the magnified
form
(see
Fig.
2-4).
The
equivalent length
of
the
magnified
sweep
is
more
than 100
divisions;
any 10
division portion
can be viewed
by
adjusting the
POSITION
and FINE POSITION
controls
to
bring the desired portion
into
the viewing
area.
When
the
MAG
switch
is
set to
XI
0
(OUT)
the equivalent
magnified
sweep
rate
can be
determined by
dividing the
TIME/DIV
setting by
10;
the
equivalent magnified
sweep
rate
is
displayed on
the
crt
readout.
VARIABLE HOLD
OFF
The
HOLD
OFF
control improves
triggering
stability
on
repetitive
complex waveforms
by
effectively
changing
the
repetition rate of the
horizontal
sweep
signal.
The
HOLD
OFF
control
should normally be
set
to
its
minimum
setting.
When
a stable display cannot be obtained with
the
TRIGGERING LEVEL
control,
the
HOLD
OFF
control
can be
carried for
an improved
display.
If
a
stable
display cannot be obtained
at
any
setting of the
LEVEL
and
HOLD
OFF
controls,
check
the
TRIGGERING
COUPLING
and
source
switch
settings.
1
1
ms
JISPLAY
LAY
—
F-\ -
-
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MAC
iNIF
ED
C
\
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r
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i
t
/
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MAG-X1
/
1
1
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\
7
!
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i
too
MS
\
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/
/
T
V
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—
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4—
MA
GNIF
MED
DISP
im
Ill
C
1960-16
Fig.
2-4.
Operation
of
sweep
magnifier.
MAINFRAME
OPERATING
MODES
The
time-base
unit
can
be operated
either as
an
independent time base
in
any
Tektronix 7100-, 7700-,
7800-,
or
7900-series
oscilloscope mainframes,
or
as
a
delayed-sweep
unit
in
those mainframes
that
have two
horizontal
compartments.
A
companion
delaying time
base
unit
is
required
for
delayed-sweep
operation. Refer
to
the delaying time-base
unit instruction
manual
for
additional information.
APPLICATIONS
The
following information
describes procedures and
techniques
for
making
basic time measurements
with the
time-base
unit installed
in
a Tektronix 7100, 7700, 7600,
or
7900-series
oscilloscope.
These
procedures
provide
enough
detail to
enable
the operator
to
adapt
them
to
other
related time
measurements.
Contact your
Tektronix
Field
Office or representative
for
assistance
in
making
measurements
that
are not described
in this
manual.
TIME-INTERVAL
MEASUREMENTS
Since time
is
a function
of
the
sweep
rate
and
the
horizontal distance
(in
divisions) that the
sweep
travels
across the
graticule
in
a calibrated-sweep
oscilloscope
system, the time
interval
between any two
points
on
a
waveform
can be
accurately measured. The
following
procedures
provide
methods
to
measure
some
of the
more
common
time-related definable characteristics
of a
waveform
such as
period, frequency,
rise time,
fall
time,
and
pulse
width.
The
procedure
for
each
of
these
measurements
is
essentially
the same,
except
for
the
points
between which
the
measurements
are
made. The
time
interval
between any two
selected points on
a
displayed
waveform
can be measured
with
basically
the
same
technique.
PERIOD
AND
FREQUENCY MEASUREMENTS
Perform the following
procedure
to
measure
the period
and
determine the frequency
of a displayed waveform:
1.
Install the
time-base
unit
in
a
mainframe
horizontal
compartment
(either
A
or
B
horizontal
in
a four-
compartment
mainframe).
2.
Connect
the signal to be
measured
to
the
vertical unit
input.
3.
Set
the
mainframe
horizontal-
and
vertical-mode
switches
to
display the time base and
vertical
units.
(Check
that
the time base
VARIABLE
(CAL
IN)
control
is
pushed
in
and
the
HOLD
OFF
control
is
in
the
MIN
position.)
4.
Set the
TRIGGERING
switches and LEVEL
control
for a
stable display (see General Operating
Information
for
selecting proper
triggering).