| 摘要 |
PURPOSE:To prevent deterioration in voice quality due to a code error by substituting an input code sequence by one frame or a previously inputted code sequence when the code error rate of the input code sequence deteriorates. CONSTITUTION:A signal which indicates the level of reception to a terminal 11 is compared by a comparing circuit 13 with a threshold level generated by a threshold value generating circuit 12 and the result is applied as a substitution control signal to a substituting circuit 14. A voice code sequence inputted to a terminal 15, on the other hand, is applied to a circuit 14 and a frame synchronizing circuit 16. The circuit 14 outputs the input voice code sequence as it is by the control signal, or outputs previous data in a storage circuit 17 to a D/A converting circuit 18 when the code error rate deteriorates. |
