| 摘要 |
PURPOSE:To apply this system to a device having various echo route characteristics to converge an echo erasing control loop by detecting the case where the gain of an echo route exceeds one and setting the gain of the echo route equivalently to <=1. CONSTITUTION:The reception signal from a reception signal input terminal 1 of the echo erasing system is applied to a speaker 4 through an amplifier 3 for speaker to louden the acoustic signal in a room. This signal is gathered by a microphone 5 and is converted to an electric signal by an amplifier 6 for microphone and is applied to a transmission signal input terminal 7. On the other hand, the reception signal is digitized by an A/D converter 10, and the digital signal is delayed and is applied to a register 11 for reception signal. The convolution between the signal stored in the register 11 and an impulse response of the echo route stored in a false impulse response register 12 is operated by a means 13, and the output is subjected to D/A conversion by a D/A converter 14 and is applied to an adder 15. This adder 15 is provided between a variable gain attenuator 18 connected to the terminal 7 and a variable gain amplifier 19 connected to a transmission signal output terminal 8 to set the gain of the echo route equivalently to <=1. |
