Cross-coupled voltage controlled oscillator with improved phase noise performance
US6680657B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 2002 |
| Grant date | Jan 20, 2004 |
| Priority date | — |
| Expiry date | Jun 6, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B5/1253
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A cross-coupled voltage controlled oscillator having reduced phase noise. A pair of bipolar transistors having common emitter connections are coupled to reduce that oscillation frequency which is determined from a tuning circuit connected across the collectors of transistors. First and second varactor diodes provide analog tuning of the circuit, and a digitally controlled capacitor provides for a selection of a band of frequencies to be tuned by the varactor diodes. A current source provides the current to the emitter connections of the bipolar transistors. Second harmonic signals generated at the emitter of the transistors are significantly suppressed by a tuned filtered trap connected to the common emitter connections. By reducing the second harmonic signals, the phase noise or the voltage controlled oscillator can be significantly improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.