Patent · US Expired

FM demodulator

US4928068A · kind A · utility

5Cited by
1References
20Claims
0Family size

Assignee

Inventor

Key dates

Filing dateMay 1, 1989
Grant dateMay 22, 1990
Priority date
Expiry dateMay 1, 2009

Classification

  • Technology area (CPC H)Electricity
  • CPC primaryH03D3/24
  • WIPO fieldBasic communication processes
  • WIPO sectorElectrical engineering

Abstract

An FM demodulator circuit uses an oscillator to provide a switch control signal synchronized to an FM signal, and a current supply to provide differentially alternating currents at first and second outputs flowing through a commutator circuit to the first and second outputs of the FM demodulator circuit. The commutator circuit is responsive to the switch control signal for alternately switching the first and second outputs of the current supply between the first and second outputs of the FM demodulator circuit thereby providing an alternating current flowing in the first and second outputs of the FM demodulator circuit which has an average value over each half cycle of the switch control signal proportional to the deviation of the frequency of the FM signal from the free-running frequency of the oscillator.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.