| 摘要 |
PROBLEM TO BE SOLVED: To correct a temperature by on-line to measure a distance precisely. SOLUTION: An FM-CW signal is output from a voltage-controlled oscillator 22 by a sweep voltage E0. The FM-CW signal is distributed by a first RF circuit 23 to be transmitted to a transceiving antenna 14, and the FM-CW signal is mixed with a received signal propagated through a route of a measuring object from the transceiving antenna 14 to output a beat signal E1. A radio wave propagation distance is found by a computer 20 based on the beat signal E1 to measure the relative distance. The FM-CW signal is distributed concurrently by a second RF circuit 33 to be transmitted to a cable 40, and the FM-CW signal is mixed with a signal returned from the cable to output a second beat signal E2. Variations of a phase and a frequency of the second beat signal E2 caused by temperature change are detected to change the sweep voltage E0 in response to the change.
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