| 摘要 |
PURPOSE:To change the level of noise inserted in the case of silence corresponding to an environment by calculating an input signal power value by adding sampled data, comparing the value with a set value, selecting noise level information and transmitting the noise level to a reception part. CONSTITUTION:A voice detection part 5 stores the three stages of noise levels with two threshold values -57dBm0 and -45dBm0 as borders, the -57dBm0 is the level of absolute silence and when the level of an input signal is lower than the -57dBm0, it is judged as silence. The level of sampled input signal power is compared with the noise level, and one noise level is selected, encoded and transmitted to a noise inserting part 7. In this case, sound/silence information is transferred to a cell assembly part 4, and the noise level is transferred to the noise inserting part 7. While receiving the noise level information transmitted from a transmission part, the noise inserting part 7 changes the level of noise at a reception part. |
