Voltage controlled oscillator with automatic center frequency calibration
US6556093B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 2001 |
| Grant date | Apr 29, 2003 |
| Priority date | — |
| Expiry date | Sep 13, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J2200/10
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A voltage controlled oscillator with automatic center frequency calibration. The frequency range of the oscillator is increased by switchable capacitor circuits which add or remove extra capacitors in parallel with the variable capacitor of the resonant circuit. Different voltage versus frequency characteristics are obtained. The switchable capacitor circuits are controlled by a detection circuit that sends a reset pulse to a feedback circuit of the VCO when a control voltage from the feedback circuit reaches predetermined low or high voltage limits of the characteristics. Upon reception of the reset pulse, the feedback circuit changes the control voltage from the reached limit into an intermediate voltage between the low and high voltage limits. The control voltage is reset in the middle of a voltage versus frequency characteristic onto which the output frequency is also centered. The VCO includes a selection circuit adapted to immediately change the value of the control voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.