| 摘要 |
<p>PROBLEM TO BE SOLVED: To quickly and efficiently perform A/D sampling of and an FFT operation on a beat signal. SOLUTION: An FM-CW radar device transmits a continuous wave, as a transmission wave, frequency-modulated depending on a modulation signal in the form of a triangular wave toward an obstruction ahead and mixes a received wave reflected by the obstruction and a preliminarily separated transmission wave to produce a beat signal, which is subjected to an A/D conversion and an FFT operation to detect the obstruction. The A/D conversion value obtained via sampling of the beat signal by the A/D converter is transferred forward by DMA. If the comparison between the distance to the obstruction detected at the nearest distance and a preset threshold determines the obstruction is the nearer, the FFT operation is performed again without resampling of the A/D conversion value and with sampling data different from the previous data.</p> |
