HP 8591C, Руководство пользователя, Страница: 69 / 373

Channel Measurements
Making Channel Measurements
Composite Second
1. Select a channel, then press Main 1 of 3
Order/Composite Triple
Beat Test
2. Perform the following steps for analyzers both without and with Option
107 (when GATING is set to NO):
a. The marker defaults to the -1.25 MHz CSO beat at the lower channel
boundary. Wait for the analyzer to return an answer. If your analyzer
does not have Option 107 installed, turn off the carrier to measure
CSO and CTB or turn off the modulation to measure CSO only.
b. To perform the carrier-to-beats test according to FCC requirements,
remove the carrier.
c. Using the knob, move the marker to the desired beat, see Figure 2-17.
Note that if the marker is not active you will need to press
Alternatively, use the NEXT BEAT key.
Press + MEASURE to zoom in on the current marker position
and measure the beat in a zero span sweep.
3. Perform the following steps if your analyzer has Option 107 installed and
you want to perform a gated (non-interfering) measurement (CSO only
with modulation turned on). Note that you will only have gotten to this
point if GATING is set to NO.
a. Press GATE in the menu to perform a gated
(non-interfering) measurement.
b. The analyzer will search for a quiet line and depending on the setting
of PAUSE it will either pause or automatically continue if it finds
a quiet line. If it does not find a quiet line it will display VIDEO
SYNC NOT RECOGNIZED. At this point you can remedy the reason,
or if a quiet line was not found because of noise, you can press
LINE SEARCH to reinitiate a quiet line search. Another possible
reason for failure to find a quiet line is that the input coupler is not in
place with its coupled leg connected to TV IN.
c. Entering line numbers and the key FLD BOTH/EVEN/ODD can be used
to manually search the vertical interval for a quiet line.
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