Fractional frequency divider
US7492852B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 7, 2007 |
| Grant date | Feb 17, 2009 |
| Priority date | — |
| Expiry date | Oct 7, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03K23/667
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A divide-by-N/(N+0.5) frequency divider is disclosed. Two pairs of flip-flops are respectively triggered by an input clock and an inverted input clock, and a frequency-dividing selector is used to select one output of the two pairs of flip-flops as frequency-divided output signal. Two latches are respectively triggered by the input clock and the inverted input clock, and a modulus selector is used to select one output of the two latches. A modulus logic circuit determines being in either N frequency-dividing mode or (N+0.5) frequency-dividing mode based on a modulus control signal. A frequency-dividing logic circuit receives output of the modulus logic circuit and an inverted frequency-divided output signal to swallow half the input clock per output cycle in the (N+0.5) frequency-dividing mode, therefore obtaining division resolution of half the input clock.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.