Phase-locked loop with clamped voltage-controlled oscillator
US5072195A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 5, 1990 |
| Grant date | Dec 10, 1991 |
| Priority date | — |
| Expiry date | Apr 5, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/10
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A phase-locked loop responsive to both phase and frequency difference between the incoming signal and the feedback signal is provided. Using a reference signal, this phase-locked loop accepts a wide range of frequencies similar to a phase-locked loop having a phase frequency detector, and also achieves the noise performance of a phase-locked loop having only a simple phase detector. In one embodiment, the phase-locked loop is a combination including first and second phase-locked loops. The reference signal is provided to the first phase-locked loop, which includes a phase frequency detector. This first phase-locked loop is used to control a second phase-locked loop, which includes a phase detector. A voltage clamp can also be provided to enhance the ability to lock a signal among several signals, or from a noisy background.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.