ON-VEHICLE COMMUNICATION DEVICE

PURPOSE:To suppress automatically the sound caused by hurtling through air inputted to a microphone at running according to a car speed by providing a frequency/voltage converter generating a DC voltage in response to the pulse repetition period and a high pass filter varying a cut-off frequency by using the DC voltage as a control input. CONSTITUTION:A voice uttered by a driver is converted into an electric signal by the 1st microphone at first, and after the signal is amplified to the 1st preamplifier 3, the signal is fed to one input of an adder 5. Further, the voice uttered by a passenger on the rear seat is converted into an electric signal by the 2nd microphone and amplified by the 2nd preamplifier 4, then the signal is inputted to other input of the said adder 5. As the car speed increases, the value of the cut-off frequency of the high pass filter 9 is increased and pleasant talking with less sound caused by hurtling through air is realized by setting the cut-off frequency in this case to a value minimizing the sound caused by hurtling through air in the range exerting no effect on the voice signal.