Operating instructions
Operating
Instructions----7387
Figure
1-6
.
Operation
of
sweep
magnifier
.
TIME-INTERVAL
MEASUREMENTS
Since the
sweep
rate
and
the
horizontal
distance
(in
divisions)
that
the
sweep
travels
across
the
graticule
in
a
calibrated-sweep
oscilloscope
system
is
a
function
of
time,
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
.
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
X10
(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
complexwaveforms
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
varied
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
.
MAINFRAME
OPERATING
MODES
The
time-base
unit
can
be operated
either
as
an
independent
time
base
in
any
Tektronix
1700-, 7800-,
or
7900-series
oscilloscope
mainframe,
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
tirne-base
unit
instruction
manual
for
additional
information
.
The
following
information
describes
procedures
and
techniques
for
making
basic
time
measurements
with the
time-base
unit
installed
in
a
Tektronix
7700-, 7800-,
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
.
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
Horiz
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
.)
REV
A
MAR
1981