Low noise reference oscillator with fast start-up
US7332979B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2005 |
| Grant date | Feb 19, 2008 |
| Priority date | — |
| Expiry date | Dec 30, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L5/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency source having a fast start-up time and low noise in steady state is presented. The frequency source includes an oscillator and a hybrid automatic gain control (AGC) loop that switches between an analog AGC loop at oscillator start up and a digital AGC loop at steady state operation. The analog AGC loop includes a peak detector connected to the oscillator and an error integrator integrating the difference between the peak detector output and a reference voltage. The digital AGC loop includes a comparator comparing the peak detector output and high/low reference voltages, an oscillator counter providing a timer signal, a digital-to-analog converter (DAC) supplied with a digital word, and a low pass filter between the DAC and the oscillator. The timer signal causes a multiplexer to select either the analog AGC loop or the digital AGC loop.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.