Fractional-N based digital AFC system with a translational PLL transmitter
US7626462B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 2, 2006 |
| Grant date | Dec 1, 2009 |
| Priority date | — |
| Expiry date | Oct 19, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/1974
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A fractional-N based Automatic Frequency Control (AFC) system for a mobile terminal is provided. In general, automatic frequency control is implemented in a frequency synthesizer to correct or compensate for a frequency error of an associated reference oscillator. The frequency synthesizer includes a first fractional-N phase-locked loop (FN-PLL) generating a baseband clock signal used by a baseband processor of the mobile terminal, a second FN-PLL generating a receiver local oscillator signal used by a receiver of the mobile terminal to downconvert a received radio frequency signal to a desired frequency, and a translational PLL generating a transmitter local oscillator signal used by a transmitter of the mobile terminal to provide a radio frequency transmit signal. The automatic frequency control is performed by applying a digital correction value, which is preferably multiplicative, to fractional-N dividers of the first and second FN-PLLs.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.