SPEAKING DEVICE HAVING HAND-FREE CONVERSATIONAL FUNCTION.

摘要

This invention relates to a speaking device having a hand-free conversation function which comprises an echo canceler (3) that can cancel the echo given by the direct acoustic coupling between a speaker and a microphone caused by a system comprising the case of the device and the grounded surface thereof and a speech switching circuit (6) in which insertion loss of speech signal is so set that its upper limit is equal to the sufficient attenuation quantity for cancelling the echo caused by the indirect acoustic coupling determined by the spatial state where the speaking device is used. A good speech quality is obtained with the processing circuit of a low cost and small size by assigning the optimum shares of the functions to the echo canceler (3) and the speech switching circuit (6) respectively.