Quadrature demodulator
US5426669A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1993 |
| Grant date | Jun 20, 1995 |
| Priority date | — |
| Expiry date | Jun 17, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/2332
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A quadrature demodulator includes a device for generating first and second reference signals having a quadrature relation with each other. A first demodulating device serves to compare phases of the first reference signal and an input modulated signal to demodulate the input modulated signal into a first binary baseband signal. A second demodulating device serves to compare phases of the second reference signal and the input modulated signal to demodulate the input modulated signal into a second binary baseband signal having a quadrature relation with the first baseband signal. A first counting device operates to count pulses of a clock signal in response to the first baseband signal. A second counting device operates to count pulses of the clock signal in response to the second baseband signal. An address signal is generated in response to the output signals of the first and second counting devices. Data representative of an absolute phase of the input modulated signal is generated in response to the address signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.