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Plotting The Response Of A Continuous Filter
Syntax fcplot(xmin, xmax, ymin, ymax, cutoff, num, den)
See Also fdplot

Description
Plots the response of a continuous filter in the current viewport, where xmin is an integer, real, or double-precision scalar specifying the minimum value on the x-axis; xmax is an integer, real, or double-precision scalar specifying the maximum value on the x-axis; ymin is an integer, real, or double-precision scalar specifying the minimum value on the y-axis; ymax is an integer, real, or double-precision scalar specifying the maximum value on the y-axis; cutoff is an integer, real, or double-precision row vector denoting the cutoff frequencies; num is an integer, real, or double-precision column vector specifying the numerator polynomial for the filter; and den is an integer, real, or double-precision column vector specifying the denominator polynomial for the filter. The x- and y-axis are log-scaled, and xmin, xmax, ymin, and ymax must be powers of 10 (e.g., 1, 10, 100).

The response function plotted is
     |        __      |2
     | num[ \/-1 w ]  |
     ------------------
     |        __      |2
     | den[ \/-1 w ]  |
where w is between xmin and xmax.

Example
The following program plots a normalized 2 pole Butterworth filter.

clear
#
num   = 1.
den   = {1., sqrt(2.), 1.}
ymin   = 1e-3
ymax   = 1e2
xmin   = 1e-1
xmax   = 1e1
cutoff = 1.
fcplot(xmin, xmax, ymin, ymax, cutoff, num, den)