| 摘要 |
PURPOSE:To enable the recognition of a distance to an obstacle by a method wherein a correlation to a time corresponding to the obstacle located in front is given to a sound given to both ears of a blind person in a device for helping him walk. CONSTITUTION:A white noise from a generator 1 is amplified in power by a power amplifier 2 and emitted continuously from an ultrasonic wave transmitter 3 into the air, as an ultrasonic band noise determined by a pass band. The output of the white noise generator 1 is given to band-pass filters 4 and 5, and an electric signal equal to the frequency spectrum of the ultrasonic band noise emitted into the air is obtained therefrom and given to one ear through an ear speaker 9. Meanwhile, a reflected wave from an obstacle is received by an ultrasonic wave receiver 10 and subjected to high-frequency amplificaion to an appropriate level by a high-frequency amplifier. This amplified output is mixed with an output from a local oscillator 6 employed proviously and is given to the other ear via an ear speaker 14. |
