Operating Instructions—434
5. To measure the amplitude of an unknown signal, dis
connect the reference signal and connect the unknown
signal to the input connector. Set the V O LTS/D IV switch
to a setting that provides sufficient vertical deflection to
make an accurate measurement. Do not readjust the
Variable V O LTS/D IV control.
6. Measure the vertical deflection in divisions and
calculate the amplitude of the unknown signal using the
follow ing formula:
any setting of the T IM E /D IV switch, the repetition rate of
the reference signal must be known. If it is not known, it
can be measured before the Variable TIM E /D IV control is
set in step 2.
4. Divide the repetition rate of the reterence signal
(seconds) by the product of the horizontal deflection estab
lished in step 2 (divisions) and the setting of the T IM E /D IV
switch. This is the horizontal conversion factor.
Signal
Am plitude
VO LTS/D IV vertical vertical
switch X conversion X deflection
setting factor (divisions)
Horizontal reference signal repetition rate
Conversion =
_
____________
(seconds)
_____________
Factor horizontal deflection T IM E /D IV
(divisions) switch setting
EXAMPLE. Assume a reference signal amplitude of 30
volts, a VO LTS /D IV switch setting of 5 V, and the Variable
VO LTS /D IV control is adjusted to provide a vertical deflec
tion of four divisions.
Substituting these values in the vertical conversion factor
formula (step 4):
Vertical
Conversion =
Factor
30 V
4 X 5 V
1.5
5. To measure the repetition rate of an unknown signal,
disconnect the reference signal and connect the unknown
signal to the input connector. Set the TIM E/D IV switch to
a setting that provides sufficient horizontal deflection to
make an accurate measurement. Do not readjust the
Variable T IM E /D IV control.
6. Measure the horizontal deflection in divisions and
calculate the repetition rate of the unknown signal using
the following form ula:
Then, w ith a V O LTS /D IV switch setting of 10, the peak-to-
peak amplitude of an unknown signal which produces a
vertical deflection of five divisions can be determined by
using the signal amplitude formula (step 6):
Signal
Amplitude
= 10 V X 1.5 X 5
75 volts
Sweep Rates. To establish an arbitrary horizontal sweep
rate based upon a specific reference frequency, proceed as
follows:
Repetition
Rate
TIM E /D IV horizontal
= switch X conversion X
setting factor
horizontal
deflection
(divisions)
EXAMPLE. Assume a reference signal frequency of 455
hertz (repetition rate 2.19 milliseconds), and a T IM E/D IV
switch setting of .2 ms, with the Variable T IM E /D IV con
trol adjusted to provide a horizontal deflection of eight
divisions. Substituting these values in the horizontal con
version factor form ula (step 4):
1. Connect the reference signal to the INPUT connec
tor. Set the V O LTS/D IV switch for four or five divisions of
vertical deflection.
Horizontal
Conversion
Factor
2.19 milliseconds
.2 X 8
1.37
2. Set the T IM E /D IV switch and the Variable T IM E /
DIV control so one cycle of the signal covers an exact
number of horizontal divisions. Do not change the Variable
TIM E /D IV control after obtaining the desired deflection.
This display can be used as a reference for frequency com
parison measurements.
Then, w ith a T IM E /D IV switch setting of 50 jus, the repeti
tion rate of an unknown signal which completes one cycle
in seven horizontal divisions can be determined by using the
repetition rate formula (step 6):
Repetition = 50 pS x 1.37 X 7 = 480 jus
3. To establish an arbitrary sweep rate so the repetition
rate of an unknown signal can be measured accurately at
This answer can be converted to frequency by taking the
reciprocal of the repetition rate (see application on Deter
mining Frequency).
2-18
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