| 摘要 |
PURPOSE:To faithfully reproduce a surround signal by adding the output signal of a voltage controlled amplifier which compares signal levels of a sum signal and a difference signal with each other to control the level of a delay signal and that of a voltage controlled amplifier, which controls the level of the sum signal by the inverted signal of the control signal from a comparator, to obtain a monaural signal. CONSTITUTION:Signals SL and SR are inputted to a sum signal generating circuit 15 and a difference signal generating circuit 16, and the sum signal from the sum signal generating circuit 15 is inputted to a voltage controlled amplifier 22 and level detected by a level detecting circuit 18. The difference signal from the difference signal generating circuit 16 is inputted to a delay circuit 17 and level detected by a level detecting circuit 19. The difference signal from the delay circuit 17 is inputted to a voltage controlled amplifier 23, and outputs from level detecting circuits 18 and 19 are supplied to a comparator 20, and voltage controlled amplifiers 22 and 23 are controlled by the output of the comparator. Outputs of voltage controlled amplifiers 22 and 23 are added by an adder 13 to obtain the monaural signal. Thus, signals of two channels are faithfully reproduced as the monaural signal without losing the surround component. |
