PLL out-of-capture range detection and lock acquisition circuit
US4523157A · kind A · utility
10Cited by
4References
2Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 24, 1982 |
| Grant date | Jun 11, 1985 |
| Priority date | — |
| Expiry date | Sep 24, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S331/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An improved PLL frequency synthesizer for producing a signal of frequency f.sub.T -f.sub.IF or f.sub.T +f.sub.IF is provided with a detection-control circuit which detects from the voltage applied to a voltage controlled oscillator (VCO) in the PLL that the VCO frequency reaches an upper or lower limit frequency and upon the detection forces the VCO to fall into the capture range. The improved PLL frequency synthesizer can acquire lock even if it has been thrown out of the capture range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.