Phase lock loop carrier generator for receiver of phase modulated carrier pulse signals
US4059805A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 1, 1977 |
| Grant date | Nov 22, 1977 |
| Priority date | — |
| Expiry date | Feb 1, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2332
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Demodulator for phase modulated carrier pulse signals or phase codes in which the pulses are coded according to a plurality of N phases of the carrier. It comprises a digital phase lock loop system for locking to a frequency equal to N times the carrier frequency which includes at least a two input phase detector, a loop integrator and a voltage controlled oscillator having an output connected to the first input of the phase detector, means for dividing by N the frequency of this oscillator and for generating a reference carrier signal. The phase codes are decoded by comparing the phases of the carrier of the phase codes to the phase of the reference signal. In order to derive from all the phase codes a train of synchronous pulses a multiphase shifter receives the carrier of the phase codes and locally generates a plurality of carriers having phase shifts equal to 0, 2.pi./N, 2.times.2.pi./N, . . . ([N/2]- 1) .times.2.pi./N with respect to the carrier of the received phase code and means are provided for generating passing through zero pulses coinciding with the passage through zero of said received and locally generated carriers. Those of said passing through zero pulses which occ…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.