JPS6468082A - Sound reproduction circuit - Google Patents

Abstract

PURPOSE:To obtain a demodulated signal that includes no amplitude-variation that may occur because of phase variation or at the time of reproduction by detecting the frequencies of output signals from respective band-pass filters with a prescribed time constant based on a signal synchronized with the changing of heads and a detection signal from a dropout detection circuit. CONSTITUTION:Reproduced RF signals in respective channels separated in frequency bands after the band-pass filters 15a, 15b are detected by frequency detection circuits 16a, 16b with a prescribed time constant. This detection is executed based on a signal synchronized with the switching between the heads 2a, 2b and a detection signal from the dropout detection circuit 19, and oscillators 17a, 17b operates depending on thus obtained detection outputs. From the oscillators 17a, 17b, modulated signals that do not include phase variation due to switching or amplitude variation at the time of reproduction are outputted. Therefore, in output signals from demodulators 18a, 18b, pulse-like noises or noises due to amplitude variation do not exist, and can be outputted without any particular processing.