Coherent demodulating device with carrier wave recovering digital circuit
US5301210A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1992 |
| Grant date | Apr 5, 1994 |
| Priority date | — |
| Expiry date | Aug 31, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0077
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A coherent demodulating device is characterized by a demodulating circuit and a carrier recovering circuit produced entirely in digital form. Two quadrature demodulation carrier waves produced by a local oscillator are mixed with a demodulation carrier signal modulated by symbols to produce analog signals. The analog signals are digitized by sampling at symbol reception frequency into incoming digital signals. A digital phase shifter phase shifts the incoming signals by a demodulation phase derived by a phase loop digital processing circuit as from error signal pulses supplied by a comparing circuit receiving outgoing digital signals from the phase shifter. The compensation for the phase and frequency differences between the demodulation and modulation carrier waves is carried out a posteriori in digital form by phase shifting the incoming signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.