Frequency lock loop having a reloadable counter without rollover
US6765446B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Sep 18, 2002 |
| Grant date | Jul 20, 2004 |
| Priority date | — |
| Expiry date | Sep 18, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/091
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency lock loop has a reloadable N counter that counts cycles of an output frequency during one cycle of a reference frequency. A VCO generates the output frequency. A VCO control drives the VCO based on the count from the counter. The VCO control may include a latch for latching the count at each reference frequency cycle. The VCO control may include a VCO driver, such as a D/A converter or proportional charge pump, connected to a voltage control as input to the VCO. The counter may be reloaded with the integer N value at each cycle of the reference frequency. The counter may decrement from the integer value at each cycle of the output frequency. A lock may occur at N times the reference frequency without regard to phase between output and reference frequencies.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.