A Rectangle function () is 1 in an interval and 0 everywhere else. This function (also called top hat or boxcar) is useful for band-pass filtering; you can use it to select values within an interval. It can also simulate a signal that is turned on during an interval or a load that is active on a part of a boundary, for example. The rectangle function is a function of one variable (the time t, for example). The default Function name is rect1.

Enter a Lower limit (the default is −0.5) and Upper limit (the default is 0.5) to specify the interval for the rectangle function. For example, if the input argument is time, enter a start and end time. This function evaluates to 1 for values within the interval from the lower limit to the upper limit. Outside the interval it evaluates to 0.