| 摘要 |
In sound target detection equipment, at least three microphones are used in a broadside array manner to ascertain the presence of a selected sound source. The outputs of the three microphones all include the sought signal S and respectively contain noise components X, U and Y. These outputs are combined to provide X-U and X-Y. These two signals are then applied as separate inputs to a discriminator which applies the rules: (a) when the input signals are both of the same polarity, the discriminator selects the input closer to zero and presents it as the output; (b) when the input signals are of opposite polarity, the device presents zero as the output. The output from the discriminator is then subtracted from one of the original microphone outputs in a manner tending to cancel out the noise contents, and the resulting signal examined for the presence of the sought signal S. The invention is applicable also to non-aural signal detection equipment.
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