Automatic frequency control method and circuit for correcting an error between a received carrier frequency and a local frequency
US5373247A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 28, 1993 |
| Grant date | Dec 13, 1994 |
| Priority date | — |
| Expiry date | Jan 28, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0069
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An AFC method is used in a demodulator, which employs a 2.sup.n -phase phase shift keying modulation system, where n is an integer greater than or equal to two, to correct an error between a received carrier frequency and a local frequency. The AFC method includes the steps of (a) subjecting an intermediate frequency signal of a signal received by the demodulator to a quadrature wave detection to obtain I-axis and Q-axis signals, (b) converting amplitude information of the I-axis and Q-axis signals into phase information which includes frequency information, and (c) correcting the local frequency based on the frequency information included in the phase information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.