| 摘要 |
PURPOSE:To control effectively the sound volume in accordance with the variance of noise between vehicle stop and running by controlling the output of a preamplifier with a control signal obtained by integrating a speed signal and a running state detection signal. CONSTITUTION:A running operation means 6 consisting of a neutral switch 10 and a clutch switch 11 outputs the running state detection signal. This detection signal value is set to a value smaller than a prescribed value when a vehicle is stopped, and the detection signal value is set to a value larger than the prescribed value when the vehicle is run, and the detection signal value is inputted to an integrator 23. This detection signal is integrated together with an engine rotation speed detection signal from an igniter 8, and the control signal proportional to the engine rotative speed is outputted and is inputted to an integrator 21 when the vehicle is stopped, and the control signal obtained by adding the engine rotative speed and a whizz proportional to this rotative speed is outputted and is inputted to the integrator 21 when the vehicle is run. The integrator 21 integrates the output of the preamplifier 1 controlled by a volume 7 and the control signal and supplies the output to a main amplifier. |
