Robust differential receiver for frequency modulated system

摘要

A robust differential receiver is described that may be used in any frequency modulated system, including short-range radio frequency (RF) communication devices. The differential receiver provides a preamble detection approach that reduces false preamble detection, a fine carrier frequency (CFO) estimation approach that provides an extended estimation range, and robust in-band and out-of-band interference detection. The described differential receiver assures that preamble detections are not falsely triggered, and that CFO estimates are based on accurately modeled preamble waveforms that have not been distorted by phase ambiguities or in-band distortion. In this manner, the described robust differential receiver assures that CFO estimates used to compensate remaining portions of detected signals are accurate, thereby reducing the likelihood that remaining portions of the detected signal will be affected by phase ambiguity distortions, thereby enhancing the differential receiver's ability to lock onto an otherwise unavailable communication channel, and/or reducing transmission errors and/or packet loss.

主权项

1. A receiver, comprising:
a detector configured to generate phase values based on a stream of baseband data that is provided to a received signal strength indicator (RSSI) module; and a preamble detection module, comprising:
a monitor configured to monitor the phase values and detect an ambiguity in the phase values;an eliminator configured to remove the detected ambiguity to produce corrected phase values;a preamble detector configured to detect a communication channel preamble sequence based on the corrected phase values; anda received signal strength indicator (RSSI) monitor configured to monitor an output of the RSSI module and report changes in a magnitude of RSSI values generated by the RSSI module to a controller configured to determine whether in-band interference is present in the detected communication channel preamble sequence based on changes in a magnitude of data filtered by a filter.