Analysis Display – The channel number and modulation type are displayed the same as analog channels. Similarly, the location and modulation type are displayed.
Digital – The digital channel’s Frequency and Average Power Level measurement replaces the video carrier level measurement and is shown in dBmV. All audio carrier and ratio (delta) measurement results are dropped. Note that the frequency of the digital channel is the center frequency for the channel, rather than the video carrier frequency.
PreFEC BER - The PreFEC BER (Pre-FEC Bit Error Rate) is the error rate of the incoming 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
PostFEC BER - The PostFEC 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.
MER - MER (Modulation Error Ratio), the digital equivalent of signal-to-noise, 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.
Adjacent Channel – Displays the channel number and modulation type of the adjacent channel.
Adjacent Video – Displays the frequency of the adjacent carrier and level measurement of the upper adjacent video carrier in dBmV.
Adjacent Channel Ratio – This display will be added in future releases of the PC-IP firmware. Displays the result of the difference in level between the primary channel’s level measurement and the measurement of the upper adjacent channel in dB. This measurement and calculation is only made if the upper adjacent video carrier is within the nominal channel bandwidth of the tuned channel.
