摘要
E. O. Brigham mentioned in the book The Fast Fourier Transform that it is extremely difficnlt to visualize the mathematical [operation of convolutional integration. He stated a general rule for determining the convolutioual integration limits, but it is yet difficult to master and use. In this letter a pattern convenient to visualizing the mathematical operation is proposed. Let f1（t） and f2（t） be functions, which can bo written as single analytic expressions in their durations [l2,r1] and [l2, r2] respectively, l1≠∞, l2≠∞,
