Software for Linear-Phase Filter Design

The Matlab Signal Processing Toolbox covers many applications with the following functions:

$$\begin{tabular}{rl} \texttt{firpm()} & (optimal Chebyshev linear-phase FIR filter design),% \footnote{Look for the older name \texttt{remez()} in Octave Forge} \\ \texttt{firls()} & (optimal least-squares linear-phase FIR filter design), \\ \texttt{fir1()} & (window method for linear-phase FIR \emph{lowpass} design),\\ \texttt{fir2()} & (window method for linear-phase FIR filter design), and\\ \texttt{invfreqz()} & (weighted least-squares method for general FIR (or IIR)\\ & filter design \cite[page 50]{JOST}). \end{tabular}$$

All of these functions are implemented in Octave (which free and open-source) as well, except that firpm is called remez in Octave (the original name used in Matlab).^11.3

Methods for FIR filter design are discussed in the fourth book of the music signal processing series [87], and classic references include [64,68]. There is also quite a large research literature on this subject.