| 摘要 |
<p>PURPOSE:To obtain a device of a high measuring accuracy by using a spectrum expansion system to make a phase modulation in two phases in an m series set to make the maximum delay time by the distance smaller than half the pulse width of one bit of the sign series. CONSTITUTION:The carrier wavs 20 for an oscillator OSC 1 is two-phase modulated 180 deg. by a phase modulator 2 depending on the m series 21 of the output of a PN generator 5, and output as a transmission signal 22. It is reflected by a distance measuring object, and received as a receiving signal 24. In this case, the maximum delay time by the distances of the signals 22 and 24 are set smaller than half the pulse width of one bit to compose the m series. The signals 22 and 24 are partially down-converted by an OSC3 6, input to a phase detecting circuit 7 respectively, and the relation of the signals 22 and 24 is found by finding the phase difference of both signals. This relative signal is input to a wave form reforming circuit 8 to make into a TTL level, and furthermore, input to an integral circuit 9 converted into a relative mean voltage, and the distance is measured by signal-processing the relative mean voltage 27.</p> |
