To load a WAV file as the input signal, click the Load File button, which will open a file dialog box. The sampling frequency is extracted from the file, and once the file is loaded, the time and frequency responses are plotted.

This section allows you to design different types of filters. Select the number of filter elements, the cut-off frequencies, and the filter type. Then, click the Make Filter button to create the filter, using the specified parameters, and to plot the frequency response of the filter.

To view the filter coefficients, click the Table or Plot buttons.

Use the two dials below to select a subsection of the signal to filter.

Click the Execute Filter button to apply the designed filter to the selected signal segment. The frequency response of the input and output are shown.

To analyze the frequency response over time, the input signal segment is divided into frames of a specified length. The frequency spectrum is calculated for each frame, and displayed as a surface plot with time and frequency as the axes.

* Note: The Play Input and Play Output buttons will only work for Windows machines (except Windows Vista).