Two-wire two-way automatic gain controller

Abstract

Abstract PURPOSE:To prevent singing and cut-off of the head and tail of speech by starting the gain control of a gain variable circuit after an echo erasing amount or a sum between the echo erasing amount and an echo loss reaches a prescribed value. CONSTITUTION:Echo calcellers 7, 7' utilize a talking signal of start of talking, starts an echo cancelling operation, generate a signal to cancel an echo signal and superimpose it on the echo signal so as to erase the echo. In this case, until the echo cancelling attenuation of the canceller 7 is increased gradually and then reaches a prescribed, the gain of a gain variable circuit 8 is kept to 0, then no singing is generated and no cut-off of the start and tail of speech is caused. Then when the echo cancelling attenuation reaches a prescribed value or over, a control circuit 9 starts the gain control of the gain variable circuit 8.

Inventors

• 👤 Kiyohisa Wakabayashi
• 👤 若林　清久
• 👤 Hiroshi Yasukawa
• 👤 博 安川
• 👤 Ryoji Kijima
• 👤 木島　良二
• 👤 Yasuo Ito
• 👤 泰雄 伊藤
• 👤 Shigeyuki Umigami
• 👤 重之 海上

Bibliographic Details