Updated: 7/10/00
There is no need to disrupt service for this test! Nearly any anlyzer and some signal level meters (such as the newer Wavetek Stealth receivers) can be used to perform this test with channels in service.
See the technical papers "How to run non-disruptive tests even if your test gear doesn't do gated measurements"
and the 4100 & 4200 In-Service Test Processor product descriptions for additional information.
If running this test at the output of a set-top converter (testing at the converter output is required starting
in the year 2000), you can use either scrambled or unscrambled channels. For scrambled channels, insert a test
signal on line 24. Some scramblers trash in-channel response during the vertical blanking interval.
When using GCR or sweep signals for the test, narrower resolution bandwidth (RBW) settings can be used to provide
increased frequency resolution. If you use 300 kHz RBW setting (the default for the Tek analyzers), the advantage
of GCR or sweep signals over a multiburst test signal is greatly reduced.
Links to tech articles:
To test at the tap, or the converter. THAT is the question
Running tests on scrambled channels
How to run non-disruptive tests even if your test gear doesn't do gated measurements