Patent ID: 8095019

Claim:
Apparatus, comprising: a digital signal processor (DSP) adapted to receive a sequence of complex sampled values associated with a modulated optical carrier and responsively provide a corresponding sequence of symbols; the DSP is configured to include three constant modulus algorithm (CMA) adaptive finite impulse response (FIR) filters, each filter processing the received sequence of complex sampled values according to a respective set of filter coefficients to provide thereby a respective sequence of symbols, a first filter exhibiting a first group delay, a second filter exhibiting a second group delay and a third filter exhibiting a third group delay, the first group delay initially being less than the second group delay, the second group delay initially being less than the third group delay; the DSP is configured to include a mechanism for adapting the filter coefficients sets to constrain the exhibited group delays; the DSP selecting for further processing the sequence of symbols provided by the second filter.