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. Also provide a Baseline (default: 0) and Amplitude (default: 1) This function evaluates to the amplitude plus the baseline for values within the interval from the lower limit to the upper limit. Outside the interval it evaluates to the baseline. You can use unit syntax to assign units to these parameters.