Patent ID: 9621274
Date: 2017-04-11
CPC Classifications: H04B

Claim:
1. An apparatus, comprising: a demodulator circuit configured to receive an optical signal carrying a plurality of data bits and a local oscillator signal, the demodulator circuit supplying a plurality of demodulated outputs; an equalizer circuit; and a first and second circuit blocks coupled to the equalizer circuit, the first circuit block providing first outputs including quadrature phase shift keying (QPSK) decoded data and the second circuit block outputting binary phase shift keying (BPSK) decoded data, the second circuit block including: a carrier recovery circuit configured to supply in-phase (I) and quadrature (Q) components associated with the modulated optical signal; a switch circuit configured to select one of the I and Q components; and a decoder circuit configured to decode the selected one of the I and Q components and output the plurality of data bits in response thereto, each of the carrier recovery circuit, the switch circuit and the decoder circuit receiving the first sequence of bits.