On-vehicle sound control apparatus
First Claim
1. An on-vehicle sound control apparatus, comprising:
- first filtering means for removing a direct current component from an electric source signal supplied from an electric source of a vehicle to produce an alternating current signal, an electric power produced by an operation of an engine of the vehicle being charged in the electric source;
second filtering means for removing a particular frequency component from the alternating current signal produced by the first filtering means to take out an alternator noise, of which a frequency changes with an engine speed of the vehicle, from the alternating current signal;
noise level calculating means for calculating a noise level in an inside of the vehicle according to the alternator noise obtained by the second filtering means; and
controlling means for controlling a volume of a sound reproduced in a sound reproducing means or a tone of the sound according to the noise level calculated by the noise level calculating means.
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Accused Products
Abstract
An electric source signal supplied from a battery of a vehicle is composed of a direct current component and an alternating current component. The alternating component is classified into an alternator noise of which a frequency changes in proportional to an engine speed of the vehicle and other noises. Also, as the engine speed is heightened, a vehicle noise in the inside of the vehicle is heightened. The direct current component of the electric source signal is removed in an alternating current component passing circuit, the other noises are removed in a band pass filter, and the alternator noise is obtained. Thereafter, a frequency of the alternator noise is calculated in a microcomputer, and a volume of a sound reproduced by a speaker of an on-vehicle stereo and a tone of the sound are adjusted according to the frequency of the alternator noise. Therefore, a driver can be entertained with a music without being disturbed by the vehicle noise.
37 Citations
10 Claims
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1. An on-vehicle sound control apparatus, comprising:
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first filtering means for removing a direct current component from an electric source signal supplied from an electric source of a vehicle to produce an alternating current signal, an electric power produced by an operation of an engine of the vehicle being charged in the electric source; second filtering means for removing a particular frequency component from the alternating current signal produced by the first filtering means to take out an alternator noise, of which a frequency changes with an engine speed of the vehicle, from the alternating current signal; noise level calculating means for calculating a noise level in an inside of the vehicle according to the alternator noise obtained by the second filtering means; and controlling means for controlling a volume of a sound reproduced in a sound reproducing means or a tone of the sound according to the noise level calculated by the noise level calculating means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification