Coherent phase detector using a frequency discriminator
AssigneeHarris Corporation
InventorsRobert Curtis Davis, Daniel Dix McRae
Life of this patent
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Abstract
A coherent phase detector using a frequency discriminator for reducing a frequency encoded signal to baseband, thereby avoiding the necessity of generating a coherent RF phase reference signal. A baseband processor is provided to compensate for error components arising in the frequency discriminator output. The baseband processor includes feedback loops for DC level correction and automatic gain correction. A novel scheme is also described for reducing the influence of interbit crosstalk on the operation of the baseband processor.
Claims7
Apparatus for use in a system for demodulating a frequency encoded signal comprising:
- frequency discriminator means responsive to said frequency encoded signal for providing a baseband signal corresponding to the derivative of the phase of said encoded signal;
- and,
- baseband processing means responsive to said baseband signal for providing an error compensated baseband signal, said baseband processing means comprising
- means for providing a timing signal related to the timing of said frequency encoded signal,
- means for integrating said baseband signal over a discrete timing interval to provide a phase shift signal representing the amount by which the phase of said frequency encoded signal has shifted over said interval,
- means for quantizing said phase shift signal into integral and fractional parts, and
- means responsive to said fractional part of said quantized phase shift signal for providing error compensation for said baseband signal whereby said baseband processing means provides an error compensated baseband signal to the remainder of said system for demodulating said frequency encoded signal.
Apparatus for processing a baseband signal derived from a frequency encoded signal comprising:
- means for providing a timing signal related to the timing of said frequency encoded signal;
- means for integrating said baseband signal over a discrete timing interval to provide a phase shift signal representing the amount by which the phase of said frequency encoded signal has shifted over said interval;
- means for quantizing said phase shift signal into integral and fractional parts;
- and,
- means responsive to said fractional part of said quantized phase shift signal for providing error compensation for said baseband signal.
Dependencies are inferred from the claim text.