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Ambient noise cancellation for voice communications device

  • US 8,472,641 B2
  • Filed: 10/06/2008
  • Issued: 06/25/2013
  • Est. Priority Date: 03/21/2002
  • Status: Expired due to Fees
First Claim
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1. A communications device, comprising:

  • a directional first microphone having a microphone output, wherein the directional first microphone is sensitive to sound coming from a predetermined direction such that voice signals are predominantly received by the first microphone;

    an omnidirectional second microphone having a microphone output, wherein the second microphone is substantially equally sensitive to sound emanating from any direction, such that voice signals and ambient noise are received by the second microphone;

    an ambient noise compensation signal generator having (i) an ambient noise compensation signal generator input connected to the second microphone output and (ii) an ambient noise compensation signal generator output, wherein the ambient noise compensation signal generator is configured to generate a compensation signal;

    a mixer having (i) a first mixer input in communication with the first microphone output and (ii) a second mixer input connected to the ambient noise compensation signal generator output and (iii) a mixer output, wherein the mixer is configured to mix the signal from the first microphone output with the compensation signal from the ambient noise compensation signal generator output;

    a transmitter having a transmitter input connected to the mixer output and a transmitter output in communication with an antenna, wherein ambient noise picked up by the second microphone is processed by the ambient noise compensation signal generator and wherein the ambient noise is attenuated by the mixer mixing the signal from the first microphone output with the compensation signal before being passed to the transmitter; and

    an enable/disable switch for enabling/disabling the ambient noise compensation signal generator, wherein when the ambient noise compensation signal generator is disabled, the output of the second microphone is provided to the mixer as the second mixer input.

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