Tektronix 545A Instruction Manual page 22

Operating
Instructions
—
Type
545A
SINGLE-SWEEP PRESENTATION
REPETITIVE-SWEEP PRESENTATION
Fig.
2-14. Comparison
of single
sweep and
repetitive
sweep presentation
of a
damped
sine
wave.
In
the repetitive
sweep
presentation,
it
is
difficult to
determine
what
is
being
presented.
However,
in
the single
sweep
presentation the
damped
sine
wave
can be
clearly seen.
The
usual oscilloscope display
formed
by a repetitive
sweep
is
entirely satisfactory for
most
applications.
How-
ever,
in
applications
where
the
displayed
waveform
is
not
repetitive or varies
in
amplitude, shape, or time
interval,
a
repetitive
sweep produces a jumbled
display.
When
ob-
serving a
waveform
of
this
type,
it
is
usually
advantageous
to use a single-sweep presentation.
The Type 545A
Oscilloscope permits
you
to
obtain a
single-sweep presentation
and
to eliminate
all
subsequent
sweeps
so that
information
is
clearly
recorded without the
confusion
resulting
from
multiple
traces.
The
single-sweep
feature
is
selected
by
placing the
HORIZONTAL
DISPLAY
switch
in
the A'
SINGLE
SWEEP
position.
In
this position,
only
Time
Base
A
is
used.
The RESET
button controls the
start
of the single
sweep.
When
the
STABILITY
control
is
set fully
clockwise or the
TRIGGERING
MODE
switch
is
in
the
AUTO,
position,
a
single
sweep
runs
immediately each
time the
RESET
button
is
depressed.
However,
if
Time Base
A
is
set for
triggered
operation with the
TRIGGERING
MODE
switch
in
other than
AUTO,
or
HF
SYNC
positions, the single
sweep
does not
occur
when
the
RESET
button
is
depressed
unless a trigger-
ing signal
is
applied
to
Time Base A.
Instead the
READY
lamp
lights to
indicate that the
sweep
is
ready
to
be
trig-
gered.
When
a triggering signal occurs, the single
sweep
runs
and
the
READY
light
goes
out.
Each time the
RESET
button
is
depressed the procedure
is
repeated.
External Horizontal Input
For special applications
you can
deflect the trace
hori-
zontally
with
some
externally derived
waveform.
This
allows
you
to use
the oscilloscope
to plot
one
function
versus another.
To
use
an
external horizontal input,
connect
the externally
derived
waveform
to the
HORIZ.
INPUT
connector
and
place
the
HORIZONTAL
DISPLAY
switch
in
either
EXT.
position.
The
horizontal deflection factor
is
continuously variable from
approximately
.2
to
approximately
15
volts
per centimeter
with
the
VARIABLE
10-1 control
and
the
HORIZONTAL
DISPLAY
switch.
Sweep
Magnifier
The
sweep
magnifier allows
you
to
expand any
two-
centimeter portion
of the
displayed
waveform
to the
full
ten-centimeter width of the
graticule. This
is
done
by
first
using
the
HORIZONTAL
POSITION
control to
move
the
2-12