Automatic frequency control (AFC) system and method using an adaptive threshold to improve accuracy of the direct current (DC) component calculation for a received signal
US6980775B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 30, 2002 |
| Grant date | Dec 27, 2005 |
| Priority date | — |
| Expiry date | Aug 20, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J7/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A radio device requires a tunable transceiver such that the transceiver can be accurately set to a desired frequency. When a signal with known frequency accuracy is being received, an offset detector can determine the frequency offset generated by the transceiver due to improper tuning. An automatic frequency control (AFC) system (100) is comprised of a tunable transceiver, an adaptive detector (102) for comparing an incoming sample from the tunable transceiver to an adaptive maximum deviation threshold for determining if a sample from the tunable transceiver should be used for the direct current (DC) component of the AFC, an offset detector (103) and an AFC control processor (105) for utilizing information from the offset detector to reduce the inaccuracy in frequency by tuning the transceiver towards the received signal frequency. The AFC control processor (105) utilizes one of more threshold levels for defining a maximum correction threshold (311) based upon the desired maximum offset correction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.