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TM 9-254
8-6.
Waveform Reading - Continued
(1)
Check the calibration of the scope horizontally, using a signal of known frequency. The output frequency
of the CALIBRATOR (9, fig. 8-8) is 1000 Hz with a voltage of 1 volt peak-to-peak.
(2)
Turn the TIME/DIV OR DLY TIME switch (3, fig. 8-10) to the .lms position. One cycle should be
displayed on the CRT.
(3)
Rotate the SWP CAL control (16, fig. 8-10) until the displayed waveform of one cycle covers exactly 10
divisions horizontally as shown in figure 8-14.
Figure 8-14. Calibrated Signal Display
(4)
To calculate the frequency of a signal you must first find the time of one complete cycle of displayed
waveform. To do this you must use the controls of the main triggering amplifier (fig. 8-10).
(5)
The TIME/DIV switch (3, fig. 8-10) controls the horizontal display time of the oscilloscope.
NOTE
Whenever you change the input signals to the vertical amplifier or the positioning of the TIME/DIV
switch (3, fig. 8-10) it may be necessary to adjust the LEVEL knob (15, fig. 8-10) to stabilize the
displayed signal.
8-20
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