Noise cancellation apparatus
AssigneeAndrea Electronics Corporation
InventorsDouglas Andrea, Martin Topf
Life of this patent
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Abstract
Apparatus for reducing acoustic background noise for use with a telephone handset or a boom microphone device or a boom headset or the like. The apparatus includes first and second microphones which are arranged such that the first microphone receives a desired speech input and the background noise present in the vicinity of the speech, and the second microphone receives substantially only the background noise. The background noise from the second microphone is converted into a corresponding electrical signal and subtracted from a signal corresponding to the speech and background noise obtained from the first microphone so as to produce a signal representing substantially the speech.
Claims13
Noise reduction apparatus comprising:
- a housing having first omnidirectional microphone means for receiving a first acoustic sound composed of speech originating from an operator operating said apparatus and background noise, and for converting said first acoustic sound to a first signal, and second omnidirectional microphone means arranged in close proximity up to about 0.5 inches to thereby act as a dipole at a predetermined angle .phi. with respect to said first omnidirectional microphone means for receiving a second acoustic sound composed of substantially said background noise and for converting said second acoustic sound to a second signal whereas the first omnidirectional microphone means and the second omnidirectional microphone means are directly connected without any intermediate circuitry to a means for subtracting;
- and
- the means for subtracting said second signal from said first signal so as to obtain a signal representing substantially said speech.
A microphone apparatus for reducing background noise, said apparatus comprising:
- a housing;
- a first omnidirectional microphone having a first pressure sensitive surface and arranged within said housing so as to receive a first acoustic sound composed of speech originating from an operator operating said apparatus and said background noise, said first omnidirectional microphone for converting said first acoustic sound to a first signal;
- a second omnidirectional microphone having a second pressure sensitive surface and arranged within said housing so as to receive a second acoustic sound composed of substantially said background noise, said second omnidirectional microphone converting said second acoustic sound to a second signal, said second pressure sensitive surface being arranged in close proximity up to about 0.5 inches at a predetermined angle with respect to said first pressure sensitive surface whereas the first omnidirectional microphone means and the second omnidirectional microphone means are directly connected without any intermediate circuitry to a means for subtracting;
- the means for subtracting said second signal from said first signal so as to obtain a signal representing substantially said speech;
- and
- wherein the first and second microphones are in close proximity to each other to thereby act as a dipole.
Dependencies are inferred from the claim text.