mattdsp

function [a,b] = eqnerror(M,N,w,D,W,iter);
% [a,b] = eqnerror(M,N,w,D,W,iter);
%
% IIR filter design using equation error method
%
% if the input argument 'iter' is specified and if iter > 1, then
% the equation error method is applied iteratively trying to
% determine the true L2 solution of the nonlinear IIR design problem
%
% M     numerator order

mattdsp

function h = cfirls(N,f,d,w,hreal)
% function h = cfirls(N,f,d,w,hreal)
% Least-squares FIR filter design with prescribed magnitude and phase
% responses and with possibly complex coefficients
%
% h     real or complex-valued impulse response
% N     desired filter length
% f     frequency grid
%       	for complex-valued filters ('hreal=0'): -1 <= f < 1
%		( '1' corresponds to Nyquist) or 0 <= f < 2

mattdsp

function x = levin(a,b)
% function x = levin(a,b)
% solves system of complex linear equations toeplitz(a)*x=b
% using Levinson's algorithm
% a ... first row of positive definite Hermitian Toeplitz matrix
% b ... right hand side vector
%
% Author: Mathias C. Lang, Vienna University of Technology, AUSTRIA
% 1997-09
% mattsdspblog@gmail.com

mattdsp

function a = iir_ap(N,f,phi,W)
% function a = iir_ap(N,f,phi,W)
% IIR allpass filter design using an equation error method
%
% a		denominator coefficients; numerator = flipud(a)
% N		filter order
% f		frequency grid; 0 <= f <= 1 ('1' equals Nyquist)
% phi	desired phase on the grid (in radians)
% W		positive weight function on the frequency grid
%

mattdsp

function h = fsamp(mag,N)
% function h = fsamp(mag,N)
% frequency sampling design of linear phase FIR filter
%
% mag ... desired magnitude response on an equidistant grid
%         between 0 and Nyquist
% N   ... filter length (N <= 2*length(mag) - 1 )
% 
% for even N the frequency grid is defined by (M = length(mag)):
%