| 摘要 |
PURPOSE:To detect earlier the approach of a moving subject by controlling an actuator which turns intermittently a microphone having directivity while setting its angle and equipping a microcomputer for outputting detection information after it processes sound pressure data. CONSTITUTION:A motor 2 is controlled by the microcomputer 6 and turns after it stops at each sound recording azimuth for the prescribed period. A sound pressure signal detected by the microphone 1 is amplified by an amplifier 7, and passes through a low-pass filter 8. Said signal is converted into a signal for enveloping a peak value in an envelope detection circuit 9, sampled by n-times and converted into a digital signal by an A/D converter 10. N-piece of sound pressure data are sequentially transmitted to the computer 6, averaged, and transferred to the address of memory to be stored. Then the computer 6 outputs an indicating signal to the motor 2, and the microphone 1 is sequentially angle-set to measure sound pressure. The average sound pressure data is stored in the memory and displayed after data processing is applied. By the shift of the peak value of the sound pressure data the shift of a sound source can be detected.
|
