Patent US 5,754,665

The object of the noise canceler of the present invention is to allow hands-free conversation from either of two microphones through a parallel construction having two noise cancelers using FIR adaptive filters. When microphone 2 (at the driver's seat) is used for conversation, microphone 3 (at the passenger seat) is used for collecting noise and a noise-reduced voice signal 105 is obtained by using FIR adaptive filter 14; and when microphone 3 is used for conversation, microphone 2 is used for collecting noise and a noise-reduced voice signal 104 is obtained using FIR adaptive filter 13. These two voice signals 104, 105 are added at adder 17 and the result outputted as voice output signal 103.