Fine tuning frequency synthesizer with feedback loop for frequency control systems
US4977613A · kind A · utility
13Cited by
7References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1988 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | Oct 17, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J5/0272
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An additional mixer is included in the feedback loop of a PLL which can be one of the local oscillators of a dual conversion system. A fine tuning frequency synthesizer is coupled to an input of the additional mixer for providing fine frequency control of the PLL. The fine tuning frequency synthesizer can include an additional phase locked loop. Also, a feedback signal for suppressing noise created by another local oscillator can also be applied to the additional mixer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.