Patent ID: 6788922
Filing Date: 2004-09-07
Classification: H03D

Abstract:
A radio FM receiver comprising:a voltage-controlled oscillator; a frequency 2-divider coupled to an output of said voltage-controlled oscillator; a quadrature combination circuit; detection and sound reproduction means connected to said quadrature combination circuit wherein said voltage-controlled oscillator, said frequency 2-divider and said quadrature combination circuit transform down a frequency of received radio signals and supply quadrature output signals for said detection and sound reproduction means; a frequency 3-divider; and switching means for selectively connecting the voltage-controlled oscillator to the quadrature combination circuit via either the frequency 2-divider or the frequency 3-divider, characterized in that the frequency 3-divider comprises: a divider circuit for supplying n cyclical output signals Vn(t) for every three VCO signal cycles, where Vn(t)=V1(tâˆ’(nâˆ’1)&Dgr;t) with n=1, . . . , 6, and &Dgr;t=the duration of half a VCO cycle; two summation networks each receiving the n cyclical output signals and each combining the n cyclical output signals with predetermined weighting factors, respectively, for forming respective quadrature components; and two low-pass filters coupled, respectively, to outputs of said two summation networks for low-pass filtering the respective quadrature components.