| 摘要 |
The present invention provides a hands-free telephone wherein near-end caller voice detection information is provided with little error, and wherein electric power saving effects are improved, and also wherein the far-end caller does not receive an unnatural impression. An echo canceller comprises: level calculating means 1, 2, and 3 for calculating the level of reception signals, input transmission signals, and residual signals; and adaptive filter 4 for inputting the reception signals and transmission input signals and outputting residual signals; echo cancellation amount calculation means 5 for calculating the echo cancellation amount from the input transmission signal level and residual signal level; voice detection threshold value control means 6 for controlling the voice detection threshold value according to the reception signal level and the echo cancellation amount; voice detection means 7 for outputting a voice detection flag using the residual signal level and the voice detection threshold value; attenuator control means 9 for controlling the suppression amount based on the reception signal level, and attenuator 10 for performing suppression according to the suppression amount. <IMAGE> |
