Convolution: Flip and Drag -- Help


Select the red signal f(t) and the green weight function g(t) using the popdown menus at right. The weight function is graphed at lower right in green. The signal is graphed at bottom left in red. Accessing these menus causes t to be reset to t = -1.

Grab the [t] slider at the bottom to increase t . The function g(t-u) is drawn in green in the lower left window. The value of t can be animated using the [>>] key, or increased or decreased by 0.01 using the [>] or [<] keys.

In the window above it, the product f(u)g(t-u) is drawn in yellow, and the area between it and the horizontal axis is shaded in blue.

In the top left window, the signed area under f(u)g(t-u) is sketched; this is the value of the convolution f*g at t.

The convolution is graphed in light gray, which is overtraced in cyan as t increases.


c 2001 H. Hohn