Basic
Applications-2230
Operators
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HORIZONTAL
DISTANCE
4998-34
Figure 6-21. Time duration.
EXAMPLE: The distance between the time-
measurement points is 8.3 divisions
(see
Figure
6-21
),
and the A SEC/DIV switch is set to 2 ms. The X10
Magnifier switch
is
pushed
in
(1
X magnification).
Substituting the given values:
Time = 8.3 div x 2 ms/div = 16.6
ms
Duration
AMPLITUDE COMPARISON
In
some applications it may be necessary to establish a
set
of
deflection factors other than those indicated
by
the
VOL TS/DIV switch settings. This
is
useful for comparing
unknown signals to a reference signal of known amplitude.
To
accomplish this, a reference signal of known amplitude
is first set to
an
exact number of vertical divisions
by
adjusting the VOL TS/DIV switch
and
Variable control.
Unknown signals can then be quickly
and
accurately com-
pared with the reference signal without disturbing the set-
ting of the VOL TS/DIV Variable control. The procedure
is
as follows.
1 . Preset instrument controls
and
obtain a baseline
trace.
2.
Apply the reference signal to either vertical channel
input
and
set the VERTICAL MODE switch to display the
channel used.
6-20
3.
Set the amplitude
of
the reference signal to
an
exact
number of vertical divisions
by
adjusting the VOL TS/DIV
switch and VOL TS/DIV Variable control.
4.
Establish a vertical conversion factor, using the fol-
lowing formula (reference signal amplitude must
be
known):
Vertical reference signal
Conversion =
____
a_m...:.p_li_tu_d_e_(,_v_o_lts""')
___
_
Factor vertical deflection VOL TS/DIV
(divisions) X switch setting
5.
Disconnect the reference signal
and
apply the un-
known signal to
be
measured to the same channel input.
Adjust the VOL TS/DIV switch to a setting that provides
sufficient vertical deflection to make
an
accurate measure-
ment.
Do
not readjust the VOL TS/DIV Variable control.
6.
Establish
an
arbitrary deflection factor, using the fol-
lowing formula:
Arbitrary vertical
Deflection = conversion x
Factor factor
VOLTS/DIV
switch
setting
7.
Measure the vertical deflection
of
the unknown sig-
nal
in
divisions
and
calculate its amplitude using the follow-
ing formula:
Unknown arbitrary vertical
Signal = deflection x deflection
Amplitude factor (divisions)
EXAMPLE: The reference signal amplitude is 30
V,
with
a VOL TS/DIV switch setting of 5 V
and
the VOL TS/DIV
Variable control adjusted to provide a vertical deflection
of
exactly 4 divisions.
Substituting these values
in
the vertical conversion fac-
tor
formula:
Vertical
30 V
Conversion =
------
= 1.5
Factor 4 div x 5 V /div
Continuing, for the unknown signal the VOL TS/DIV
switch setting is 1 and the peak-to-peak amplitude spans
--
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