The Filter Response Graph displays the filter frequency response. The phase graph is usually hidden, because the phase of the filters this program designs is always linear with frequency, and thus the phase graph is usually uninteresting.
The graph also displays the graph design information. This allows the user user to compare the filter frequency response to the desired design frequency response.
Some filter specifications will not result in a valid FIR filter. For example, extremely narrow transition widths, or in some cases, transition widths that are too wide, or a filter length that is too low a value, will result in a plot with scattered points, or even a totally blank graph.
The user can use the mouse to see the frequency and amplitude of a point in the graph.
The user can also select regions of the graph and zoom in in on a region to get more precise readings from the graph.
If desired, the phase graph can be displayed. The phase graph is usually hidden. The phase of the filters this program designs is always linear with frequency, and thus the phase graph is usually uninteresting.
Several graph settings can be changed.