| 摘要 |
PURPOSE:To prevent the generation of the burst sound of an AM stereophonic receiver by holding a phase information signal for synchronous detection when the negative peak value of an amplitude-modulated signal exceeds a fixed value. CONSTITUTION:Intermediate-frequency signal SIF is supplied to detecting circuit 20 for an amplitude-modulated signal its detection output is supplied to detecting circuit 30 for the degree of modulation. Then, when the level of the detection output exceeds a fixed value, control circuit 21 is brought under control to hold phase information signal cosphi. Intermediate frequency signal SIF is divided by phase information signal cosphi to obtain aural signal component SA, which is synchronously detected by synchronous detectors 4 and 5 to obtain stereophonic signals L and R. On the other hand, when an error phase information signal is obtained, a value right before is held to provide the prevention of the generation of a burst sound. |
