Security system with dynamic range enhancement for FM demodulation
US7792511B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 2007 |
| Grant date | Sep 7, 2010 |
| Priority date | — |
| Expiry date | Feb 26, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0055
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A system and method for communicating between a base and a remote device in a security system. The base receives an audio signal from a telephone network via a panel and then frequency modulates the audio signal at a carrier frequency to generate an FM signal. The remote device receives the FM signal from the base, determines a phase error signal representing the phase error between the received FM signal and an output signal of a voltage controlled oscillator, determines a difference between the carrier frequency and a center frequency of the voltage controlled oscillator, and, if there is a difference, then changes the center frequency of the voltage controlled oscillator to match the carrier frequency of the FM signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.