As the doohickey hummed away at a very highfrequency-a whopping 6 billion cycles per second-the "piezoelectric" material in it produced a warbling electric field that was easy to detect.
Usually, the edge of image is the highfrequency of frequency field.
通常，图像的边缘为频率域的高频分量。
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This system is designed by modularization, so it has high integration, wide application field, suits different frequency signal acquisition and analyse.