Tektronix 1L40, Инструкция по эксплуатации

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Operating Instructions— Type 1L40
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Spectrum n u ll between lobes
Fig. 2 -2 2 . A p p lica tio n o f the p lu g -in oscilloscope m a gnificatio n
feature.
Repetition Rate: The pulse repetition rate is measured by
switching the dispersion to zero so the analyzer becomes
a fixed tuned receiver. The sweep is then triggered on the
signal and the display becomes a time domain function.
The procedure is as follows:
1. Tune the signal to the display center with the RF CEN­
TER FREQ and the IF CENTER FREQ controls.
2. Change the DISPERSION RANGE switch to kHz position,
then decrease the DISPERSION to 0. Uncouple the RESOLU­
TION control and turn to the fully clockwise position. The
analyzer is now a fixed frequency device.
3. Set the plug-in oscilloscope Trigger Source selector to
Int position and adjust the triggering controls for a stable
triggered display. The IF CENTER FREQ— FINE control may
require slight adjustment to displace the spectrum null point
from the sweep start. See Fig. 2-12.
4. Set the Time/CM switch of the oscilloscope so that
several pulses of the applied signal are displayed (see
Fig. 2-11). Be sure the Variable Time/CM control of the
oscilloscope is in the Calibrated position. The number of
pulses displayed is now a function of the sweep rate and
signal PRF.
5. Measure the number of centimeters between 2 or more
pulses on the graticule.
(A ) Signal m odulated by a 1 kHz signal. VIDEO FILTER
OFF. LIN mode.
(C) A m plitud e m odulated signa l. 2 kHz sidebands.
(B) Same signal as A, VIDEO FILTER ON.
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m m m w w sm m m m
(D ) Same signal as C. VIDEO FILTER ON.
2-21
Fig. 2 -2 3 . Using the VIDEO FILTER to improve the resolution ca p abilities o f the analyzer.