Differential phase shift keying modulator
AssigneeNational Semiconductor Corporation
InventorHee Wong
Life of this patent
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Abstract
A differential phase shift keying (DPSK) modulator utilizes time-domain filtering techniques. The DPSK modulator includes a data scrambler which receives a serial digital data input signal and generates an output signal representing the dibit value of the serial input sequence. The dibit signal is differentially encoded and then provided to a history generator which produces phase modulating vectors utilizing pulse density modulation (PDM). The carrier waveform is then modulated utilizing the modulating vectors to generate a DPSK output signal.
Claims6
A differential phase shift keying DPSK modulator for modulating a carrier waveform to provide a phase modulated output signal, the DPSK modulator comprising:
- (a) data scrambler means responsive to a digital data input signal sequence for generating a corresponding sequence of dibit signals;
- (b) encoding means for differentially encoding the sequence of dibit signals;
- (c) a dibit history generator responsive to the sequence of differentially encoded dibit signals for generating corresponding phase modulating vectors;
- and
- (d) modulating means for modulating the carrier waveform utilizing the phase modulating vectors to generate the phase modulated output signal.
A differential phase shift keying DPSK modulator for modulating a carrier waveform to provide a phase modulated output signal, the DPSK modulator comprising:
- (a) a data scrambler responsive to a serial digital data input sequence for generating a corresponding sequence of dibit signals;
- (b) encoding means for differentially encoding the dibit signals;
- (c) weighting means responsive to the sequence of differentially encoded dibit signals for generating a plurality of digital signals representing the binary weighted values of the corresponding differentially encoded dibit signals;
- (d) phase modulating means for phase modulating the plurality of digital signals;
- (e) density modulating means for density modulating the phase modulated digital signals;
- (f) scaling means for scaling the density modulated digital signals according to the breakdowns of a step response to generate at least one phase modulating vector;
- and
- (g) waveform modulating means for modulating the carrier waveform utilizing the at least one phase modulating vector to generate the phase modulated output signal.
Dependencies are inferred from the claim text.