| 摘要 |
PURPOSE:To improve the fidelity of the speech having a small amplitude waveform and to decrease quantization noise by amplifying the original speech input waveform by a nonlinear amplifier having two kinds of reciprocal characteristics. CONSTITUTION:A frequency dividing circuit 2 generates a necessary signal by receiving a reference clock signal from an oscillating circuit 1. Clock circuits F1-Fb are various function circuits such as display circuits or the like. A microphone 3 is connected to an inverse logarithmic amplifier 4 and further the speech signal of analog quantity is coded to digital quantity by a coding circuit 5. The signal coded in said circuit is successively stored in a sound recording part 6 where the signal obtd. from the circuit 2 is successively read out and writing is accomplished. The signal read out from the part 6 is synthesized to an analog signal by a decoding circuit 7. The analog signal is nonlinearly amplified by a logarithmic amplifier 8 and is sounded from a speaker 9. The original speech input waveform from the microphone 3 is coded in the state in which the original sound waveform having the small amplitude is largely amplified and therefore fidelity is considerably improved. |
