Variable frequency LC oscillator using variable impedance and negative impedance circuits
US5486794A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1994 |
| Grant date | Jan 23, 1996 |
| Priority date | — |
| Expiry date | Dec 15, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B7/06
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A variable frequency oscillator which can be implemented entirely in a semiconductor chip, which is variable over a broad frequency range and which has relatively low phase noise, includes a variable impedance circuit, a reactive load connected to an output terminal pair of the variable impedance circuit, and a negative impedance circuit having an output terminal pair connected to the output terminal pair of the variable impedance circuit. In one embodiment, the negative impedance circuit has an input terminal pair connected to an input terminal pair of the variable impedance circuit to serve as a positive feedback path for the variable impedance circuit. In another embodiment, the negative impedance circuit includes a pair of level shifters which ensure that the variable impedance circuit is properly biased and works in a forward active region.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.