| 摘要 |
PURPOSE:To plan improvement of reliability of measurement by tracting and synthesizing two waves which have different carrier frequencies and comparing the amplitude of synthesized waves with prescribed normal value. CONSTITUTION:Electrical oscillations of frequencies f1, f2 which synchronize with normal signals generated at the generating part 1 of a time axis and are generated in synchronizing oscillating parts 2, 2a are transmitted to media as supersonic waves of carrier frequencies f1, f2 through transmitting/receiving shared parts 3, 3a and transmitting/receiving wave parts 4, 4a. After these supersonic waves are reflected by a measuring object 8, received 4, 4a, they are converted into electrical oscillations and transmitted to a subtracter 9 through the shared parts 3, 3a. Next, in the subtracter 9 the receiving signals of the frequencies f1, f2 are subtracted and synthesized, the synthesized waves are amplified 5, and transmitted to an amplitude comparison/time measuring part 6. And in the measuring part 6 the amplitude of the synthesized waves is compared with a prescribed threshold, receiving normal signals are output at the time when the amplitude of the synthesized waves exceeds the threshold, first of all commenced time measurement is ended as soon as the supersonic waves are transmitted and measuring time is output. The measuring time is transmitted to a distance operation part 7 and the distance up to the object 8 is calculated. |
