Method and apparatus for providing coarse and fine tuning control for synthesizing high-frequency signals for wireless communications
US6137372A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1998 |
| Grant date | Oct 24, 2000 |
| Priority date | — |
| Expiry date | May 29, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/199
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for synthesizing high-frequency signals is disclosed that overcomes integration problem associated with prior implementations while meeting demanding phase noise and other impurity requirements. In one embodiment, a phase-locked loop (PLL) frequency synthesizer is disclosed having a voltage controlled oscillator (VCO) with a variable capacitance that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance, and the continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance. In a more general terms, a frequency synthesizer is disclosed having a first variable and a second capacitance circuits and frequency control circuitry to coarsely tune the output frequency by adjusting the first control signal and to finely tune the output frequency by adjusting the second control signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.