Oscillator circuit having reduced phase noise
US6462627B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 25, 2000 |
| Grant date | Oct 8, 2002 |
| Priority date | — |
| Expiry date | Aug 25, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B5/1243
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The present invention, generally speaking, allows for a substantial reduction in oscillator phase noise by modifying the transfer function of a portion of the oscillator, e.g., by adding a zero to the transfer function. Modifying the transfer function reduces the open-loop gain of the oscillator but achieves a desired phase compensation, allowing the oscillator to be operated at the resonance of the resonator instead of off resonance. In an exemplary embodiment, the transfer function is modified by choosing a capacitance value such that, instead of operating as a bypass at the frequency of interest, adds a zero to the transfer function of the oscillator and causes a change in frequency characteristics, achieving an increase in the effective Q of the oscillator. This increase in effective Q translates directly into reduced phase noise. Phase noise improvement in the range of 3dB has been demonstrated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.