| 摘要 |
PURPOSE:To secure the quality of signal and to attain effective encoding, by detecting the period of pitch of a voice signal for obtaining an average power of the voice signal within a time being an integer multiple of the period of pitch, and encoding the result. CONSTITUTION:The voice signal (v) is applied to a pitch extracting circuit 1 and to an accumulating adder 3 via a delay circuit 2. Further, the circuit 2 supplies the voice signal (v) to the adder 3 until the circuit 1 detects the period of pitch of the voice signal (v). The adder 3 performs adding processing within a time being an integer multiple of the period of pitch, e.g., a time limited to N-times the time of the period of pitch, with counting a clock signal by means of a built-in counter. When the adder 3 obtains the amplitude voltage of the voice signal (v) and accumulates the voltage, the average voltage value of the voice signal (v) is obtained with a divider 4 dividing the summed value with the N. Thus, the average power of the voice signals within one frame is applied to the encoding circuit and the signals are encoded digitally at each frame. |
