Patent ID: 7158588

Claim:
A method for detecting at a receiver a continuous phase modulation (“CPM”) waveform signal transmitted by a transmitter, wherein said CPM waveform: (A) has a known maximum allowable carrier frequency offset, (B) comprises a pattern of binary tones comprising a predetermined number of a first binary tone followed by a predetermined number of a second binary tone, the pattern repeating a predetermined number of times, (C) has a symbol rate that is one of a predetermined number of known symbol rates, (D) is received and sampled at a predetermined sample rate, wherein said method of detecting uses Fourier Transforms (“FTs”) containing a predetermined number of bins N such that each bin comprises a predetermined number of frequencies, said method comprising the steps of: (a) partitioning the received CPM waveform signal into blocks such that each block comprises a predetermined number of samples; (b) normalizing the predetermined number of bins N of the FTs; (c) performing a FT on a first one of said blocks to thereby generate a set of FT bins; (d) determining a baud rate of the received CPM waveform; (e) determining the difference in Root Mean Square (“RMS”) amplitude between the samples in a first portion of said first one of said blocks and the samples in a second portion of said first one of said blocks; (f) determining a Tone Bin Distance (“TBD”) as a number of bins as a function of said baud rate; (g) determining a Carrier Frequency Window (“CFW”) containing a predetermined number of bins N of said set of FT bins including a bin zero; (h) determining, for each bin in said CFW, a largest cumulative amplitude of: (1) said each bin in the CFW; (2) the bin one TBD greater than said bin in the CFW; (3) the bin one TBD less than said bin in the CFW; and (i) determining that: (1) the baud rate determined in step (d) is approximately the symbol rate divided by twice a symbol repetition factor of one of said predetermined number of known symbol rates, (2) the RMS amplitude difference determined in step (e) is less than a first predetermined threshold, and (3) the largest cumulative amplitude value from step (h) is greater than a second predetermined threshold, to thereby detect said CPM waveform at the receiver.