HP 8591C User Manual page 12

There are two measurement modes within the cable TV analyzer mode of
operation:
Channel measurement mode
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System measurement mode
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Channel measurement mode is used to perform channel-by-channel
measurements. That is, you can execute a single measurement on a single
channel.
System measurement mode is used to create test plans that allow you to
execute selected (or all) measurements on a selected channel or range of
channels. After setting up these test plans, system measurement mode
is used to execute a test plan immediately, or schedule the tests to be
performed at a later tune. Measurement results can be stored to a RAM
card, sent to the screen for viewing, or dumped to a printer.
3. The HP 85721A with supported analyzer is a TV receiver (Option 107
required). You can listen to the sound and see the picture simultaneously.
This allows you to quickly identify picture quality problems such as noise,
distortion, hum, and ingress.
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