| 摘要 |
PURPOSE:To make fine adjustments of level diagram regardless of an attenuation quantity which is limited on an exchange by encoding a speech signal outputted from the exchange and attenuating the level for the encoded speech signal. CONSTITUTION:A speech signal sent from a telephone terminal 1 is connected to a signal attenuation quantity adjustment part 6 by the exchange function part 5 of the exchange 2 and the signal attenuation quantity adjustment part 6 adjusts the level to some extent; and the speech encoding part 7 of the speech encoding device 3 encodes the speech signal and sends the result to a signal attenuation quantity adjustment part 8, which adjusts the level and sends the signal to an opposite party through a time-division multiplexing device 4. The encoded speech signal which is inputted to the signal attenuation quantity adjustment part 8 is connected to one of ROMs 9-11 by a selector 12 which is a mechanical rotary switch, and its level is converted into bits correspond to 1dB, 2dB, and <=3dB. Consequently, the attenuation quantity of the encoded speech signal can be adjusted in 1dB units. |
