Plural-differential, phase-shift-keyed modulation, communication system
AssigneeRockwell International Corporation
InventorSantanu Dutta
Life of this patent
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Abstract
A plural-differential phase shift keying (PDPSK) communication system has a transmitter (22) for encoding digital data as plural differentials of phase between successive pairs of channel symbols of a carrier, and a receiver (24) with a plurality of phase differential detectors (32, 48) connected in cascade for determining the plural differentials of phase of the incoming signals to achieve a bit error rate independent of frequency offsets and thereby an improved rate of signal acquisition.
Claims17
A plural-differential, phase shift keyed digital communication system comprising:
- a plural-differential phase shift keying transmitter for transmission of a carrier with each of a succession of data words of a digital signal encoded therein as at least three differentials of phase between at least four channel symbols of the carrier;
- a plural-differential phase shift keyed receiver for decoding the at least three phase differentials into the data word encoded by the transmitter;
- and,
- said transmitter includes means for transmitting at least three reference phase signals at the beginning of each transmission of a digital signal from which a first three words of the digital signal are decoded by the receiver.
In a differential, phase shift, keying receiver, the improvement being a plural-differential, phase shift keying demodulator, comprising:
- means including
- a plurality of differential stages for determining the phase differences between a plurality of channel symbols of a plural-differential phase shift keyed transmission of digital data transmitted at a symbol rate, and
- a single means, connected between a first one and a last one of the plurality of differential stages, for matched filtering of the channel symbols;
- and
- means responsive to said plurality of differential stages for decoding the digital data.
A plural-differential, phase shift keying digital communication system comprising:
- a plural-differential phase shift keying transmitter for transmission of a carrier with each of a succession of data words of a digital signal encoded therein as at least three differentials of phase between at least four channel symbols of the carrier;
- a plural-differential phase shift keyed receiver for decoding the at least three phase differentials into the data word encoded by the transmitter;
- and,
- each of said words has only one bit.
In a differential, phase shift, keying receiver, the improvement being a plural-differential, phase shift keyed demodulator, comprising:
- means including:
- an input for receipt of a plural-differential phase shift keyed transmission of digital data transmitted at a symbol rate;
- a plurality of differential stages for determining the phase differences between a plurality of channel symbols of a plural-differential phase shift keyed transmission of digital date transmitted at a symbol rate;
- a single means connected between the input and the first one of the plurality of differential stages for matched filtering of the channel symbols;
- and
- means responsive to said plurality of differential stages for decoding the digital data.
In a double-differential, phase-shift-keying receiver, the improvement being a double-differential, phase-shift-keyed demodulator, comprising:
- an input for receiving a double-differential, phase-shift-keyed transmission of digital data;
- two sequential, differential detection levels for determining a difference between the phase differences between three channel symbols, comprising two successive pairs, of a double-differential, phase-shift-keyed transmission of digital data;
- wherein,
- a first differential detection level includes two differential detectors in parallel, wherein a first of said detectors is for determining a phase difference between the first of said pair of channel symbols and a second of said detectors is for determining a phase difference between the second of said pair of channel symbols,
- and a second level of differential detection having a single-differential detector operating on an output of said first level differential detectors,
- a filtering means connected to said first level differential detectors for matched filtering of the channel symbols;
- and,
- means responsive to the said second level differential detector for decoding the digital data.
Dependencies are inferred from the claim text.