| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem wherein highly accurate measurement cannot be carried out without using a clock having a short frequency and high performance, when acquiring a ranging time only by the number of counts of a clock signal. SOLUTION: A fire-control signal from a pulse generation part 22 and an output signal from a high-speed peak hold circuit 20 are imparted to F/F 22, to thereby acquire 'the time from fire-control signal output until peak detection of a search wave'. An output signal from a peak hold circuit 9 and a clear signal from F/F 25 are imparted to F/F 24, to thereby acquire 'the time from peak detection of a reflected wave until rise of a reference clock immediately thereafter'. As for outputs from the F/F 22 and the F/F 24, a logic sum thereof is taken by an OR circuit, and integration thereof is performed by an analog integrator 10. The result is quantized by an A/D converter 13 and stored in a register 14. The accurate elapsed time from search wave transmission until reflected wave detection is calculated from a discrete value of a ranging counter 11, a quantized value stored in the resister 14 and a fixed value set beforehand in a fixed value register 27. COPYRIGHT: (C)2004,JPO&NCIPI
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