Specifications

6.
7.
Observe
the
DM44
readout.
lt
should
indicate
approximately
1
.000
ms.
Using the
A TIME
control to
position
the
time-
measurement
point
to
each suceeding
square'wave
leading
edge, observe
that
respective
readouts
indicate
approximately
2.000
ms,
3.000
ms, 4,000
ms,
etc.
A
TRIGGER
INPUT
COUPLING
CHECK
1.
Perform steps
1
through
5
of the
preceding
Basic
4658
Timins Check.
2.
With the
A
TRIGGER
COUPLING
lever set
to
AC,
verify that
the dc
component
of
input
is
rejected.
The
display should
show an
almost
flat top and
bottom
of the
square
wave, with
centering
around
the
graticule
center
line. Three
graticule
divisions
denotes
a
300-mV signal
(set
vertical
VOLTS/DlV
as
required).
3. Move
the A
TRIGGER
COUPLING
lever
to LF
REJ
and
verify rejection
of the
1-kHz square-wave
input.
Display should
show
differentiated
spikes
as a
result
of
filtering circuits.
4.
Move
the
A
TRIGGER
COUPLING
lever
to
HF REJ.
The
display
should
show
rounding
off
of
the
rising
and
falling
edges of
the square'wave
input.
High-
frequency
filtering
causes
exclusion
of
components
making
up the
square
edges.
5.
Move
the
A
TRIGGER
COUPLING
lever to
DC and
adjust
the
A
TRIGGER SLOPE
LEVEL
control,
if
necessary,
to
align the
bottom
edges of
the square
wave
with the
graticule
center
line. Display
should
show
all
ac and
dc
components
of
the
input signal.
EXTERNAL
HORIZONTAL
GAIN
CHECK
1.
Perform
steps 1
through
5
of
the
preceding
Basic
4658
Timing
Check.
2. Set
the
A
TIME/DlV
control
to X'Y.
3. Set
the
CH
1
VOLTS/DIV
switch
to 50
m.
4. The
crt display
should
show
two
dots with a
horizon-
tal
separation
of
approximately
5.75
to 6.25
divisions.
@
40
4658/DM44
Operators