Self-referenced differential decoding of analog baseband signals

摘要

Apparatus and methods of differentially decoding analog baseband signals are described. In one aspect, a wireless communication apparatus includes a baseband filtering stage and a differential decoder stage. The baseband filtering stage receives a DPSK analog baseband signal differentially encoded with phase shift differences in successive symbol periods. The baseband filtering stage selectively passes frequencies in the DPSK analog baseband signal within a passband frequency range to produce a filtered analog signal. The differential decoder includes a delay circuit and a combiner circuit. The delay circuit produces from the filtered analog signal a reference signal that preserves values of a feature of the filtered analog signal for one symbol period. The combiner circuit combines values of a feature of the filtered analog signal during a current symbol period with values of the reference signal to produce a resultant signal representing a differential decoding of the DPSK analog baseband signal.