Hybrid analog and digital control of oscillator frequency
US9705514B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 26, 2014 |
| Grant date | Jul 11, 2017 |
| Priority date | — |
| Expiry date | Dec 20, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/0994
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A hybrid analog/digital control approach for a digitally controlled oscillator augments a digital control path with an analog control path that acts to center the digital control path control signal within its range. The digital control path controls a first group of varactors within an oscillator tank circuit using a digital filter and a delta sigma modulator, which generates a dithered control signal for at least one of the first group of varactors. The analog control path controls a second group of varactors in the tank circuit but actively tunes only one varactor at a time. The analog control path performs relatively low bandwidth centering of the digital control signal resulting in negligible impact on PLL bandwidth, stability, and noise performance. Instead, the digital control path dominates in setting the PLL dynamic and noise behavior, and has reduced range requirements due to the centering action.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.