Digitally controlled frequency generator including a crystal oscillator
US5179359A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 16, 1992 |
| Grant date | Jan 12, 1993 |
| Priority date | — |
| Expiry date | Mar 16, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03B21/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A digitally controlled oscillator (100) having a first oscillator circuit (108) for providing an oscillator signal F.sub.o of a defined frequency and a digital divider (110) for dividing the oscillator signal F.sub.o by a selectable number controlled by a digital word for providing a clock signal F.sub.clk. A second oscillator circuit (104) receives the clock signal F.sub.clk and provides a low frequency signal F.sub.c. The second oscillator circuit includes a digitally controlled resonator element (112) for determining the frequency of the low frequency signal and has a center frequency dependent upon the clock signal. Circuitry (118, 120, 138) is included for providing first and second pairs of quadrature phase shifted signals derived from the clock signal F.sub.clk and the low frequency signal F.sub.c and from the oscillator signal F.sub.o, respectively. Finally, a mixer (136) is provided for mixing the first and second pairs of quadrature phase shifted signals for providing a single high frequency output signal F.sub.out which varies in accordance with the digital word.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.