Automatic volume adjusting apparatus
First Claim
1. An automatic volume adjusting apparatus comprising:
- a volume adjusting device connected between a sound signal source and a loudspeaker;
means for generating a first signal corresponding to the level of a sound signal supplied from the sound signal source to the loudspeaker;
means for generating a second signal corresponding to the level of a composite sound which includes sound generated by the loudspeaker and ambient noise;
means for processing the first and second signals so as to generate a third signal corresponding substantially to only the level of the ambient noise;
means for sampling the third signal at predetermined intervals;
means for holding the output of the sampling means for a predetermined period of time; and
means for controlling, according to the output of the holding means, the level of the sound signal passing through the volume adjusting device.
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Abstract
An automatic volume adjusting apparatus comprises a volume adjusting device connected between a sound signal source and a loudspeaker; a first rectifier circuit for generating a first signal having a D.C. level corresponding to the level of a sound signal supplied from the colume adjusting device to the loudspeaker; a microphone and a second rectifier circuit for generating a second signal having a D.C. level corresponding to the level of a composite sound constituted by the sound generated by the loudspeaker and the ambient noise; a subtraction circuit for generating a third signal having a level corresponding to the level difference between the first and second signals, i.e. the level of the ambient noise; a gate circuit for sampling the third signal at predetermined intervals; and an integrator circuit for holding the output of the gate circuit for a predetermined period of time. The output of the integrator circuit controls the volume adjusting device.
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Citations
5 Claims
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1. An automatic volume adjusting apparatus comprising:
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a volume adjusting device connected between a sound signal source and a loudspeaker; means for generating a first signal corresponding to the level of a sound signal supplied from the sound signal source to the loudspeaker; means for generating a second signal corresponding to the level of a composite sound which includes sound generated by the loudspeaker and ambient noise; means for processing the first and second signals so as to generate a third signal corresponding substantially to only the level of the ambient noise; means for sampling the third signal at predetermined intervals; means for holding the output of the sampling means for a predetermined period of time; and means for controlling, according to the output of the holding means, the level of the sound signal passing through the volume adjusting device. - View Dependent Claims (2, 3, 4, 5)
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Specification