| 摘要 |
PURPOSE:To make it possible to extract a pitch frequency stably in a high speed in a comparatively simple unit by utilizing the output of a band pass filter group. CONSTITUTION:After input sound signals have the high band emphasized by pre-emphasis circuit 3 after amplification, they are applied to BPF group 5 which divides the frequency range of 200Hz to 6KHz into 16 to 30 channels. Signals of each divided channel are outputted to terminal 9 as the feature quantity of the sound wave as they are, and channel outputs of frequencies higher than the pitch frequency are outputted to terminal 10. Though these output signals are supplied to peak value detection holding part 12 through adder 11, a short pulse train is outputted after a prescribed time because a reset signal is supplied previously. This output is applied to reset signal control part 13, and it is possible to extract the pitch frequency stably by mutual operations of peak value holding part 12 and reset signal control part 13. |
