Operating Instructions—Type 422 AC-DC
Channel 1 (reference) Channel 2
50%
Amplitude
level
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loscope trigger the signal source This can be done by con
necting the signal at the GATE OUT connector to the input
of the signal source. Set the LEVEL control fully clock
wise, TRIGGERING Mode switch to AUTO and adjust the
TIME/DIV switch for the desired display. Since the signal
source is triggered by a signal that has a fixed time relation
ship to the sweep, the output of the signal source can be
displayed on the CRT as though the Type 422 were trig
gered in the normal manner.
Multi-Trace Phase Difference Measurements
Phase comparison between two signals of the same fre
quency can be made using the dual-trace feature of the
Type 422. This method of phase difference measurement
can be used up to the frequency limit of the vertical sys
tem. To make the comparison, use the following procedure.
Fig. 2-18. Measuring time difference between two pulses.
measurement is being made) in relation to the center hori
zontal line.
10. Adjust the horizontal POSITION control so the
Channel 1 (reference) waveform crosses the center hori
zontal line at a vertical graticule line.
1. Set the Input Coupling switches to the same position,
depending on the type of coupling desired.
2. Set the vertical Mode switch to either CHOPPED or
ALT. In general, CHOPPED is more suitable for low-
frequency signals and the ALT position is more suitable for
high-frequency signals. More information on determining
the mode is given under Dual-Trace Operation in this sec
tion.
11. Measure the horizontal distance between the
Channel 1 waveform and the Channel 2 waveform (see Fig.
2-18).
12. Multiply the measured distance by the setting of the
TIME/DIV switch. If sweep magnification is used, divide
this answer by 10.
EXAMPLE. Assume that the TIME/DIV switch is set to
50 jus, the magnifier is on and the horizontal distance
between waveforms is 4.5 divisions (see Fig. 2-18).
Using the formula:
Time Delay
TIME/DIV
setting
horizontal
distance
(divisions)
magnification
3. Set the TRIGGERING Coupling switch to CH 1.
4. Connect the reference signal to the INPUT 1 connec
tor and the comparison signal to the INPUT 2 connector.
The reference signal should precede the comparison signal
in time. Use coaxial cables or probes which have similar
time delay characteristics to connect the signals to the IN
PUT connectors.
5. If the signals are of opposite polarity, pull the IN
VERT switch out to invert the Channel 2 display. (Signals
may be of opposite polarity due to 180° phase difference;
if so, take this into account in the final calculation.)
6. Set the VOLTS/DIV switches and the VARIABLE
VOLTS/DIV controls so the displays are equal and about
five divisions in amplitude.
Substituting the given values:
Time Delay
50 ms X 4.5
10
The time delay is 22.5 microseconds.
Normal Trigger Generator
Ordinarily, the signal to be displayed also provides the
trigger signal for the oscilloscope. In some instances, it may
be desirable to reverse this situation and have the oscil-
7. Set the TRIGGERING controls to obtain a stable
display.
8. Set the TIME/DIV switch to a sweep rate which dis
plays about one cycle of the waveform.
9. Move the waveforms to the center of the graticule
with the vertical POSITION controls.
10. Turn the VARIABLE TIME/DIV control until one
cycle of the reference signal (Channel 1) occupies exactly
eight divisions between the second and tenth vertical lines
2-26
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