| 摘要 |
<p>PURPOSE:To measure a distance stably with high accuracy by detecting the phase difference between radio frequency sent and received signals by a spread spectrum system which has a wide frequency band in terms of time and calculating the relation with a light velocity. CONSTITUTION:A balanced modulator 6 imposes spread spectrum modulation on the output signal of a carrier oscillator 7 with the output signal of a code generator 8, and a transmitter 5 amplifies the modulated signal and sends its radio wave from an antenna 3 through a circulator 4. Its reflected wave is received by the antenna 3 and the circulator spread signal which is passed through the circulator 4 and amplified by a radio frequency stage 11 is multiplied by a 2nd balanced modulator 10 by the output signal of a code generator 9 to perform reverse spread modulation. This reverse spread signal is used to hold the synchronism of the generator 9 through a synchronizer 12 and the phase difference between the code sequence signals A and B of a transmission part and a reception part is detected 13 to find the propagation time (t) corresponding to the phase difference, thereby finding the distance to an object from the time (t) and light velocity. Consequently, the distance is measured stably with high accuracy without being disturbed nor affected by the environment.</p> |
