function [mag,pbr,sbr] = frespHBF(f,f1,f2,phi,fp,msg)%[mag pbr sbr] = frespHBF(f,f1,f2,phi,fp,msg)	%Compute the frequency response, the passband ripple and the stopband ripple % of a Saramaki HBF. If msg is non-null, a plot is made.% fp is the passband edge.% phi is used by designHBF.% Handle the input argumentsparameters = {'f' 'f1' 'f2' 'phi' 'fp' 'msg'};defaults = { NaN NaN NaN 1 0.2 '' };for i=1:length(defaults)    parameter = char(parameters(i));    if i>nargin | ( eval(['isnumeric(' parameter ') '])  &  ...     eval(['any(isnan(' parameter ')) | isempty(' parameter ') ']) )        eval([parameter '=defaults{i};'])    endendif isnan(f)    f = linspace(0,.5,1024);endif isstruct(f1)	% Presume that f1 is a {.val,.csd} struct    f1 = [f1.val];endif isstruct(f2)	% Presume that f2 is a {.val,.csd} struct    f2 = [f2.val];endf1 = f1(:); f2 = f2(:);Npts = length(f);w = 2*pi*f;z = exp(j*w);cos_w = real(z);n2 = length(f2);F2 = zeros(size(w));for i = 1:n2    F2 = F2 + f2(i)*cos(w*(2*i-1));endF2 = F2*2;mag = evalF1(f1,F2); if nargout > 1 | ~isempty(msg)    passband = 1:floor(2*fp*(Npts-1) +1);    stopband = Npts + 1 - passband;    pbr = max( abs( abs(mag(passband)) -1 ) );    sbr = max( abs(mag(stopband)) );endif ~isempty(msg)    clf    subplot(211)    F1 = evalF0(f1,z,phi);     hndl(1) = plot(f,abs(F1),'--'); hold on;    hndl(2) = plot(f,phi*abs(F2),':');    hndl(3) = plot(f, abs(mag),'-'); hold off;    legend(hndl,'F1','F2','HBF')    title(msg);    hold on; grid on    axis([0 0.5 0 1.1])    subplot(212)    plot(f,dbv(mag))    axis([0 0.5 -150 10])    grid on    msg = sprintf( ' pbr=%.1e', pbr );    text(0.0, -10, msg, 'VerticalAlignment', 'top');    msg = sprintf( 'sbr=%.0fdB ', dbv(sbr) );    text(0.5, dbv(sbr), msg, 'HorizontalAlignment', 'right', ...      'VerticalAlignment', 'bottom');    drawnow;    set(gcf,'MenuBar','none');    set(gcf,'NumberTitle','off');    set(gcf,'Name','HBF Frequency Response');end