Experimentation with an adaptive noise-cancellation filter

The presence of noise in speech has severely adverse effects on speech produced by a low-bit-rate voice terminal. This paper describes an adaptive noise-cancellation filter that was designed to suppress the broad-band, nonstationary, and intense noise often encountered in military tracked vehicles, helicopters, and high-performance aircraft. This adaptive noise-cancellation filter was developed for real-time operation using a TMS32010 microprocessor. The filter was tested under various environmental conditions with a wide range of filter parameters. According to our measurements, it reduces the noise floor by 10 to 15 dB without degrading the voice quality.