Communication apparatus with ambient noise reduction

摘要

Noise reduction circuitry for a communication apparatus can apply different noise reduction transfer functions, depending on whether a listening device is connected to the apparatus. If no listening device is connected, the noise reduction transfer function can be adapted for use with microphones (12) and speakers (28) that form an integral part of the communication apparatus, which may be a cellular telephone. If a listening device is connected, the noise reduction transfer function can be adapted for use with microphones (12) and speakers (28) that form a part of the listening device. This allows the noise reduction circuitry to provide improved noise reduction performance.

主权项

1. Noise reduction circuitry, comprising:
a first input, for receiving signals from at least one first microphone; a second input, for receiving signals from at least one second microphone; and a detector for determining whether a second microphone is connected to the second input; wherein the noise reduction circuitry is adapted to generate a noise cancellation signal for outputting through a first speaker proximate to said first microphone by applying a first transfer function to the signals received from the first microphone when it is determined that no second microphone is connected to the second input; and is adapted to generate a noise cancellation signal for outputting through a second speaker proximate to said second microphone by applying a second transfer function to the signals received from the second microphone when it is determined that a second microphone is connected to the second input, wherein the second transfer function is different from the first transfer function.