Microphone-array apparatus and method for extracting desired signal
First Claim
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1. A microphone-array apparatus comprising:
- a plurality of microphone elements for receiving acoustic signals;
first delay means connected to the microphone elements, for delaying their output signals for different periods of time to output a plurality of delayed signals;
first weighted summation means connected to the first delay means, for weighting and summing up the plurality of delayed output signals to extract desired signals from the signals produced by the microphone elements while at the same time reducing unnecessary signals contained in the received acoustic signals;
fictitious desired signal generating means for electrically generating a fictitious desired signal;
first adding means for adding the fictitious desired signal from the fictitious desired signal generating means and the output signal of each of the microphone elements;
second delay means connected to the first adding means, for delaying the added signals therefrom in the same manner as in the first delay means; and
weighting value determining means connected to the second delay means and the fictitious desired signal generating means, for computing weighting values of the first weighted summation means in a manner to minimize a predetermined measure through using the plurality of delayed output signals from the second delay means and the fictitious desired signal.
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Abstract
An acoustic signal is received by a plurality of microphone elements and their outputs are delayed by delay means and weighted and summed up by weighted summation means, obtaining a noise-reduced output. A fictitious desired signal is electrically generated and the weighting values of the weighted summation means is determined based on the fictitious desired signal and the outputs of the microphone elements when receiving substantially only noises.
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Citations
29 Claims
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1. A microphone-array apparatus comprising:
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a plurality of microphone elements for receiving acoustic signals; first delay means connected to the microphone elements, for delaying their output signals for different periods of time to output a plurality of delayed signals; first weighted summation means connected to the first delay means, for weighting and summing up the plurality of delayed output signals to extract desired signals from the signals produced by the microphone elements while at the same time reducing unnecessary signals contained in the received acoustic signals; fictitious desired signal generating means for electrically generating a fictitious desired signal; first adding means for adding the fictitious desired signal from the fictitious desired signal generating means and the output signal of each of the microphone elements; second delay means connected to the first adding means, for delaying the added signals therefrom in the same manner as in the first delay means; and weighting value determining means connected to the second delay means and the fictitious desired signal generating means, for computing weighting values of the first weighted summation means in a manner to minimize a predetermined measure through using the plurality of delayed output signals from the second delay means and the fictitious desired signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A method for receiving an acoustic signal with a plurality of microphone elements and electrically processing the outputs of the microphone elements to produce a desired signal having reduced therefrom undesired signals, the method comprising:
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a step of receiving the undesired signals by the plurality of microphone elements during a silent period of the desired signal; a step of adding the respective outputs from the plurality of the microphone elements and an electrically generated fictitious desired signal; a first delay step for subjecting each of the added outputs to delays of different time period to produce a plurality of delayed outputs for each of the added outputs; an arithmetic operation step for computing weighting values from the outputs of the first delay step and the fictitious desired signal so as to minimize a predetermined measure; a second delay step for delaying the outputs of the respective microphone elements in the presence of the desired signal in a manner similar to the first delay step; and a weighted summation step for weighting and summing up the outputs of the second delay step with the weighting values obtained in the arithmetic operation step. - View Dependent Claims (26, 27, 28, 29)
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Specification