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ICFR how to collect & calculate

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ICFR how to collect & calculate

Anybody idea how to retrieve from cmts and/or calculate?

Unfortunately, neither of

Unfortunately, neither of those are trivial to collect / calculate.

https://broadbandlibrary.com/frequency-response-testing/ has some good information on what it is and how to measure it.

You will likely want to use this method to determine ICFR

"deriving ICFR from adaptive equalizer (or pre-equalizer) coefficients for single carrier quadrature amplitude modulation (SC-QAM) signals"

Other options could include calculating it from UTSC data directly.

D3.0 and D3.1 have different methods for collecting Equalizer Coefficients

D3.0 they can be retrieved by using SNMP there is both Pre (from CM)


and Post Coeffiients ( from CMTS)
available (Pre and Post Equalization)

D3.1 has a different mechanism, you use SNMP to trigger a PNM Coeffients (docsPnmCmCtlTest) test which creates a binary file which is typically uploaded via TFTP

Here is a good explanation of how the calculation would be performed. https://www.zcorum.com/wp-content/uploads/Pre-Equalization-Final.pdf

Nice, the preeq i already had

Nice, the preeq i already had, struggled a bit with the inverse fft, but now i seem to have something.
Thanks so much for the links to the docs, that helped me out.
BTW indeed the 3.1 retrieval process is a jurassic disaster :-)

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