To prepare a VSB measurement
This task shows you how to load and view the 8 VSB signal located on the
Signals Disk. If you have your own 8 VSB signal, use the steps below and
enter the demodulation parameters for your signal.
1. Initialize the analyzer:
Press [
Instrument Mode
], [
receiver
], then press:
89410A: [
input section (0-10 MHz)
].
89441A: [
RF section (0-10 MHz)
].
Press [
Preset
].
Press [
Instrument Mode
], [
vector
].
Press [
System Utility
], [memory usage], [configure meas memory)], [max time pts], 4096.
2. Supply an 8 VSB signal to the channel 1 INPUT or perform the following steps
to load an 8 VSB signal from the Signals Disk into the analyzer’s time-capture
RAM:
Insert the Signals Disk into the internal disk drive.
Press [
Save/Recall
], [
default disk
], [
internal disk
].
Press [
Return
], [
catalog on].
Rotate the knob to highlight 8VSB.CAP
Press [
recall more
], [
recall capture buffer
], [
enter
].
3. Turn on averaging:
Press [
Average][average on].
4. Measure and scale the displayed trace:
Press [
Measurement Restart], [Auto Scale].
When you measure time-capture data, the analyzer automatically sets its
frequency span and center frequency to that used to capture the data.
Therefore, you did not need to set these parameters in the above steps.
If you are not measuring time-capture data, you must set the center
frequency, frequency span, and range. If these parameters are incorrect,
the analyzer may not lock to your carrier, measurement speed may be
reduced, or you may see excessive errors in the demodulated results. For
details about setting these parameters, see ‘’Carrier locking’’, ‘’Input Range’’,
and ‘’Span considerations’’ in the Video Demodulation Concepts chapter.
The next task, ‘’To determine the center frequency for a VSB signal.’’,
shows you how to determine the correct center frequency.
Using Video Demodulation
(Opt. AYH)
9 - 2
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