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PHASE
DIFFERENCE
MEASUREMENTS
(Unapplied
to CS-1020 and 1010)
This procedure is useful in measuring the phase difference
of signals of the same frequency.
Procedure:
1. Apply the two signals to the CH1 and CH2 INPUT jacks,
setting the vertical MODE to either CHOP or ALT mode.
2. Set the SOURCE to the signal which is leading in phase
and use the VOLTS/DIV to adjust the signals such that
they are equal in amplitude. Adjust the other controls for
a normal display.
3. Use the SWEEP TIME/DIV and VARIABLE to adjust the
display such that one cycle of the signals occupies 8
divisions of horizontal display.
Use the ¥ POSITION to bring the signals in the center of
the screen.
Having set up the display as above,
one division now
represents 45° in phase.
4. Measure the horizontal distance between corresponding
points on the two waveforms.
Using the formula:
Phase difference = Horizontal distance (div) x 45°/div
1 cycle
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Comparison
signal
Phase difference
Fig. 21
[EXAMPLE]
For the example, the horizontal distance is 1.7 divisions.
(See Fig. 21)
Substituting the given value:
The phase difference = 1.7 (div) x 45°/div = 76.5°
The above setup allows 45°
per division but if more ac-
curacy
is required the SWEEP TIME/DIV may be changed
and magnified without touching the VARIABLE control and
if necessary the trigger level can be readjusted.
In this
case, the phase difference
can be obtained
from
the SWEEP TIME/DIV setting for 8 divisions/cycle and the
new
SWEEP
TIME/DIV
setting
changed
for higher
ac-
curacy,
by using the following formula.
24
Phase difference = Horizontal distance of new sweep range
(div) x 45°/div
New SWEEP TIME/DIV setting
Original SWEEP TIME/DIV setting
Another simple method of obtaining more accuracy quickly
is to simply use x 10 MAG for a scale of 4.5°/div.
Phase difference
One cycle adjusted to occupy 8 div.
Phase difference
Expanded sweep waveform display.
Fig. 22
RELATIVE MEASUREMENT
If the frequency and amplitude of some reference signal are
known, an unknown signal may be measured for level and
frequency
without
use
of the
VOLTS/DIV
or
SWEEP
TIME/DIV for calibration.
The measurement
is made in units relative to the reference
signal.
* Vertical Sensitivity
Setting the relative vertical sensitivity
using i reference
signal.
Procedure:
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