| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a receiving circuit for a Doppler radar that measures a wind velocity without using a VCO and a mixer. <P>SOLUTION: The receiving circuit for the Doppler radar includes an optical heterodyne receiver 7 for output of a beat signal of a difference frequency of a receiving light and a local oscillating light, an AD converter 13 for sampling the signal of the optical heterodyne receiver 7, a plurality of band pass filters 12 in which each cut-off frequency is integer times as high as a Nyquist frequency, a frequency analyzing part 14 for Fourier transforming a time series signal sampled in the AD converter 13 for each time gate to calculate a peak frequency of each power spectrum, a filter requirement deciding processing part 9 for selecting and switching a prescribed band pass filter from among the plurality of band pass filters 12 in accordance with velocity information from its own machine velocity information output part 8 and calculating a Doppler shift frequency by the wind velocity on the basis of the peak frequency, and a wind velocity calculating part 15 for calculating the wind velocity on the basis of the Doppler shift frequency by the wind velocity. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
