Hands-free mobile telephone using echo canceller LSI

The authors describe a newly developed echo canceller LSI and a hands-free mobile telephone using the LSI chips. The LSI is of digital signal processor (DSP) type, and the hardware of the LSI is optimized as an echo canceller for use with hands-free mobile telephones. The architecture of the LSI is suitable for echo canceller processing and for easy implementation of software. The LSI is designed to interface with an external μ-law PCM codec. A hands-free mobile telephone using this LSI has been developed which enables natural conversation even during double talk by suppressing howling