Constrained least square FIR filter design for multiband filters.

Syntax

b = fircls(n,f,amp,up,lo)
fircls(n,f,amp,up,lo,'design_flag')

Description

• f is a vector of transition frequencies in the range from 0 to 1, where 1 corresponds to half the sampling frequency (the Nyquist frequency). The first point of f must be 0 and the last point 1. The frequency points must be in increasing order.
• amp is a vector describing the piecewise constant desired amplitude of the frequency response. The length of amp is equal to the number of bands in the response and should be equal to length(f)-1.
• up and lo are vectors with the same length as amp. They define the upper and lower bounds for the frequency response in each band.

• trace, for a textual display of the design error at each iteration step.
• plots, for a collection of plots showing the filter's full-band magnitude response and a zoomed view of the magnitude response in each sub-band. All plots are updated at each iteration step.
• both, for both the textual display and plots.

Example

n = 50;
f = [0 0.4 0.8 1];
amp = [0 1 0];
up = [0.02 1.02 0.01];
lo = [-0.02 0.98 -0.01];
b = fircls(n,f,amp,up,lo,'plots');  % plots magnitude response

Algorithm

See Also

References