Phase-interpolator based PLL frequency synthesizer
US8233578B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 2007 |
| Grant date | Jul 31, 2012 |
| Priority date | — |
| Expiry date | Apr 8, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/033
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A phase lock loop frequency synthesizer includes a phase rotator in the feedback path of the PLL. The PLL includes a phase detector, a low pass filter, a charge pump, a voltage controlled oscillator (“VCO”), and a feedback path connecting output of the VCO to the phase detector. The feedback path includes a phase rotator connected to the output of the VCO and to an input of a frequency divider. Coarse frequency control is implemented by adjusting the input reference frequency to the phase detector or by adjusting the divider ratio of the frequency divider. Fine frequency control is achieved by increasing or decreasing the rotation speed of the phase rotator. The phase rotator constantly rotates phase of the VCO output, thereby causing a frequency shift at the output of the phase rotator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.