b = firls (n, f, a) ¶b = firls (n, f, a, w) ¶FIR filter design using least squares method. Returns a length n+1 linear phase filter such that the integral of the weighted mean squared error in the specified bands is minimized.
The vector f specifies the frequencies of the band edges, normalized so that half the sample frequency is equal to 1. Each band is specified by two frequencies, to the vector must have an even length.
The vector a specifies the amplitude of the desired response at each band edge.
The optional argument w is a weighting function that contains one value for each band that weights the mean squared error in that band.
a must be the same length as f, and w must be half the
length of f. n must be even. If given an odd value,
firls increments it by 1.
The least squares optimization algorithm for computing FIR filter coefficients is derived in detail in:
I. Selesnick, "Linear-Phase FIR Filter Design by Least Squares," http://cnx.org/content/m10577
Package: signal