Sunrise Global and CM500 IP, CM250 IP, CM100 IP manual Viewing Files Downstream, Upstream

Chapter 5

Viewing Files

Downstream

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The results of the Downstream DOCSIS channel measurements are displayed providing information about the performance of the network at the location where the data was saved.

Rate - This is the result of the downstream Data Rate test that was stored. The test must be checked on the Limits setup screen and properly configured in the Cable Modem Setup screen to provide accurate results. See Appendix A for details on setting up an FTP server for these tests.

Level - This is the amplitude level of the downstream DOCSIS channel in dBmV (APL).

MER - This is the MER of the downstream DOCSIS channel. MER (Modulation Error Ratio) is the digital equivalent of signal-to-noise and is the measurement of the demodulated digital signal in the noise (and other impairments) of its environment. This measurement is based on constellation statistics and is the ratio of where the data actually plots on a constellation to the ideal center of the constellation decision window. A minimum of 22 dB MER is needed for 64 QAM, 28 dB for 256 QAM.

Pre FEC BER - The Pre FEC BER (Pre-FEC Bit Error Rate) is the error rate of the downstream DOCSIS signal prior to being corrected by the FEC (Forward Error Correction) circuitry in the Install Profiler. A minimum of 1.0 E-7 should be expected, although FEC may be able to correct errors as high as 1.0 E-6

Post FEC BER - The Post FEC BER (Post-FEC Bit Error Rate) is the error rate of the signal after the FEC has resolved and corrected all of the errors it can. Any errors not corrected by the FEC will impair DOCSIS transmissions and decrease throughput.

1.0E-9 is typical performance although any errors <1.0 E-0 will reduce the data transfer rate.

Upstream

The results of the Upstream DOCSIS signal measurements are displayed providing information about the performance of the network at the location where the data was saved.

Rate - This is the result of the upstream Data Rate test that was stored. The test must be checked on the Limits setup screen and