This applet demonstrates how the idea of convolution -- which we have explored in the continuous domain -- can also be applied in the discrete domain that the computer operates in. The applet is identical in functionality to the 1D Convolution applet except that students adjust sample values rather than drawing continuous functions.
Students interested in gaining a better understanding of how two functions are convolved discretely.
Click and drag in the top graph window to create an input function. Click and drag in the middle window to create a filter with which to convolve the input function. Slide the slider in the middle to "slide" the filter function over the input function. Notice that the third window contains the immediate product of the input function and the filter function. Note also that the immediate magnitude of the convolved function (in the bottom window) is equal to the area of the product signal.