| 摘要 |
PURPOSE:To reduce the increase in the transmission quantity due to the improvement of articulation by increasing a sampling frequency for a consonant part and a cut-off frequency of a low pass filter circuit offering a large articulation improvement effect higher than those for a vowel part offering only less effect. CONSTITUTION:Since no consonant is detected for a period T1, a consonant detection signal 32 is not outputted. Since a control circuit 10 does not output a cut-off frequency switching signal 33 and a sampling frequency switching signal 34, a cut-off frequency of a low pass filter circuit 45 is 4kHz and a sampling frequency from a sampling circuit 3 or the like is 8kHz. A coded data D is written in a voice data memory 7 and a clock is not inputted to a consonant period information generating circuit 11, nothing is written in a consonant period information memory 8. Since a consonant is detected for a period T2, a signal 32 is outputted, signals 33, 34 are outputted from the control circuit 10, the cut-off frequency is 8kHz and the sampling frequency is 16kHz and the coded data D is written in the memory 7. Since a clock is inputted to the circuit 11, the information representing the period is written in the memory 8. |
