6.
Observe
the DM44 readout.
It
should indicate
approximately 1.000
ms.
7.
Using
the
6.
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
465B Timing Check.
2. With the A TRIGGER COUPLING lever
set
to
AC,
verify that the
de
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
VOL
TS/DIV
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
de
components
of
the input signal.
EXTERNAL HORIZONTAL GAIN CHECK
1.
Perform
steps
1 through 5
of
the preceding
Basic
465B Timing Check.
2.
Set
the A
TIME/DIV
control
to
X·Y.
3.
Set
the
CH
1
VOL
TS/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 465B/DM44 Operators
@
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