| 摘要 |
PURPOSE:To improve the quality of reproduced voice by selecting an optimum sampling point in the down-sampling of a low frequency component so as to code the amplitude level of the sample point and the sampling pattern. CONSTITUTION:A significant point extracting device 101 of a variable density sampler 100 samples down 160 sample points handled in the unit of one processing into 20 sample points with the processing unit time of a signal being 20ms and with an output 9 of a band pass filter 8 having, e.g., 8kHz. In this case, (20-N) sets closest to the original wave are used as sample points after down-sample in order to select the most significant sample points in response to the complicated waveform of a base hand signal 9. Then a pattern matching device 102 compares a selected sample point with a pattern stored in a diction ary 103 to obtain the pattern with the highest coincidence in the dictionary. A coder 120 output a code identifying the pattern obtained by the matching device 102 and a code displaying an amplitude level of the sample to a transmis sion line 20. |
