| 摘要 |
PROBLEM TO BE SOLVED: To enable observation by an auditory sense by converting a low-frequency sound wave itself in an inaudible range, or a low frequency wave motion or vibration insensible as a sound even when converted into a sound wave, into a sound in an audible frequency band. SOLUTION: Real-time processing is performed as follows. An infrasonic input signal 11 is pretreated and then converted into digital signal data by an A/D converter 22. Waveform data are written in a waveform memory 23. Then, the waveform data are read out repeatedly at high speed during a period determined by cycle data of the waveform stored in a cycle memory 33 and converted into an analog signal in an audible frequency band having a continuous waveform similar to the original waveform by a D/A converter 16. |
