Frequency synthesizer with FM modulation
US4994768A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1990 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Mar 26, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/0958
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency synthesizer (10) for providing a modulated output signal (fo) includes a reference frequency signal (fr) and a voltage controlled oscillator (14). For dividing the frequency of the output signal from the voltage controlled oscillator (14) by a divisor, a programmable divider (16) is coupled to the output of the voltage controlled oscillator (14). To produce a phase-locked loop in which the frequency of the output signal from the voltage controlled oscillator (14) is equal to the frequency of the reference frequency (fr) signal multiplied by the divisor, a phase detector (12 ) having a first input coupled to the reference frequency signal (fr), a second input coupled to the output of the programmable divider (16), and an output coupled to the input of the voltage controlled oscillator (14) is also provided. A first integrator (24) for integrating a modulating signal provides an integrated signal and a first control signal. Similarly, a second integrator (25) coupled to the first integrator (24) for integrating the integrated signal provides a second control signal. A differentiator ( 36, 42 and 48) coupled to the second integrator (25) differentiates the second control s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.