Specifications

1. Connect
a
line
frequency
signal
to
the Channel 2
input.
2. Set
the VERT
MODE ALT
switch
out and
the
Channel 2
INVERT switch
in. Adiust
the
Channel
2 VOLTS/DlV
and
VAR controls
so that
the
Channel
2
display
is
about
the same
amplitude
as the
undesired
portion
of
the Channel
1 display
(see
Figure
17A).
3.
Depress
the
ADD
push
button.
Slightly
readiust the
Channel 2
VAR VOLTS/DlV
control
for maximum
cancellation
of the
undesired signal
component
(see
Figure 1781.
AMPLITUDE
COMPARISON
Repetitious amplitude
comparisons
of
unknown signals
with
a
reference signal
(e.9.,
on
an assembly
line
test)
may
be
easily
and
accurately
made using
the
4658. To accom-
plish
this,
a reference signal of
known amplitude
is
first
set
to an
exact number
of
vertical
divisions
by adjusting the
VOLTS/DlV and the VAR
VOLTS/DlV controls.
Unknown
signals can then
be
quickly
and
accurately com-
pared
with the
reference
signal
without
disturbing the
setting of the
vAR voLTS/DlV control.
The
procedure
is
as
follows:
Set
the amplitude
of the
reference
signal
to an
exact
number
of
vertical
divisions
by adjusting the
VOLTS/
DIV and
VAR VOLTS/DlV controls.
1.
2.
Establish
following
be known:
Vertical
Conversion
Factor
vertical
def lection X
(divisions)
VOLTS/D
IV
switch
setting
a
vertical conversion
factor, using
the
formula
(reference
signal amplitude
must
reference signal amplitude
(volts)
3.
For
the
unknown
signal,
adjust
the
VOLTS/DIV
switch
to
a setting
that
provides
sufficient
vertical
deflection tci
make
an accurate
measurement.
Do
not
readjust the
VAR
VOLTS/DlV
control.
4.
Establish
an arbitrary
deflection
factor, using
the
following
formula:
Arbitrary
Vertical VOLTS/DlV
Def
lection
=
Conversion
X
switch
Factor
Factor
setting
5.
Measure the
vertical
deflection of the
unknown signal
in divisions and
calculate its
amplitude
using
the
following
formula:
Unknown
Arbitrary Vertical
Signal
=
Def lection X Deflection
Amplitude
Factor
(divisions)
@
46
4658/DM44 Operators