| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an inexpensive handsfree telephone device with low power consumption and a small calorific value, which can suppress an echo and howling in a period from the start of a call to convergence of an echo canceller. <P>SOLUTION: An attenuator 107 is inserted into a transmission signal path. The number of estimation times of a line echo in an LEC 110 is counted by an estimation counter 108. A count value of the estimation counter 108 shows a degree of convergence of the LEC 110. A control unit 105 sets an attenuation initial value in the attenuator 107 when a call is started, and sets an attenuation amount of the attenuator 107 to zero when the count value counted by the estimation counter 108 exceeds a prescribed estimation counter threshold. If the count value is one or above and under the estimation counter threshold, the attenuation amount is kept to an initial value when a sound volume detected by a speech detection unit 106 is under a sound volume threshold, and the attenuation amount obtained by adding an addition attenuation value to the initial value is set in the attenuator 107 when the sound volume is equal to the sound volume threshold or above. <P>COPYRIGHT: (C)2012,JPO&INPIT |
