| Description | RxMER provides an in-channel received Modulation
Error Ratio (MER). RxMER is defined as an estimate,
provided by the demodulator, of the ratio:
(average constellation energy with equally likely
symbols) / (average squared magnitude of error vector)
RxMER is measured just prior to FEC (trellis/Reed-Solomon)
decoding. RxMER includes the effects of the
HFC channel as well as implementation effects of the
modulator and demodulator. Error vector estimation
may vary among demodulator implementations. The CMTS
RxMER is averaged over a given number of bursts at
the burst receiver, which may correspond to transmissions
from multiple users. In the case of S-CDMA mode,
RxMER is measured on the de-spread signal. |