Patent ID: 9319147
Filing Date: 2016-04-19
CPC Classification: H04B

Claim Text:
1. An apparatus comprising: a front-end circuit configured to mix an optical input signal and an optical reference signal to generate a first plurality of electrical digital measures of the optical input signal; and a digital processor configured to process the first plurality of electrical digital measures in a manner that enables the digital processor to recover data encoded in the optical input signal both for a case that the optical input signal is QPSK-modulated and for a case that the optical input signal is QDB-modulated; wherein the digital processor comprises an equalizer configured to perform equalization processing in a manner that causes equalized signal samples generated by the equalizer to be located substantially on a single constant radius on a complex plane regardless of whether the optical input signal is QPSK-modulated or QDB-modulated; and wherein the digital processor is configured to recover the data using the equalized signal samples.