PLL frequency synthesizer
US4797637A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1987 |
| Grant date | Jan 10, 1989 |
| Priority date | — |
| Expiry date | Aug 24, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/185
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A PLL frequency synthesizer comprises a voltage controlled oscillator which oscillates in response to a frequency signal corresponding to a control signal to be input and which outputs the frequency signal as an output of said PLL frequency synthesizer; a multiplier means for multiplying a reference frequency signal to be input; a mixer for mixing the frequency signal which is output from the voltage controlled oscillator and the multiplied reference frequency signal which is output from the multiplier, and for outputting a frequency signal representative of a difference therebetween; a variable frequency divider for dividing the difference frequency signal at a variable dividing ratio; a fixed frequency divider for dividing the reference frequency signal at a predetermined dividing ratio; a frequency phase comparator for detecting a phase difference between an output signal from the variable frequency divider and an output signal from the fixed frequency divider and for outputting a phase difference signal therebetween; a filter for removing high frequency components of the phase difference signal which is supplied as the control signal to the voltage controlled oscillator; and a …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.