fsbuild.m

很多matlab的源代码

% FSBUILD Signal reconstruction from Fourier series coefficients.
%
% FSBUILD is a script file that allows for signal reconstruction.



% ADSP Toolbox: Version 2.0 
% For use with "Analog and Digital Signal Processing", 2nd Ed.
% Published by PWS Publishing Co.
%
% Ashok Ambardar, EE Dept. MTU, Houghton, MI 49931, USA
% http://www.ee.mtu/faculty/akambard.html
% e-mail: [e-mail]
% Copyright (c) 1998


clc,echo off,disp(' Signal Recostruction from Fourier Series Coefficients')
disp('Please enter relevant information at each prompt')
%Prompt for relevant information:
T=input('Time Period : ');
d=1;sy=input('Half wave Symmetry(0=N, 1=Y) : ');if sy==1,d=2;end
lmax=input('Number of NONZERO Harmonics to be used: ');lm=min(20,lmax);
nh=d*lmax-d+1;k=1:d:nh; %Choose all harmonics if d=1 or odd ones if d=2
kk=k(1:lm);ll=length(kk);
a0=input('Average value : ');disp(' ')
disp(' Enter coefficients as an array or function of k e.g. (1/pi)./k')
disp(' If all coefficients are zero enter 0 or simply hit ENTER')
disp(' If arrays, both a(k) and b(k) must be the same length')
ak=input('Coefficients a(k)= : ');if isempty(ak),ak=0;end
bk=input('Coefficients b(k)= : ');if isempty(bk),bk=0;end
f=(0.05:.05:lm)/T; %Set up frequency array for envelope
sf=input('Smoothing window in single quotes (Hit ENTER for no smoothing): ');
if isempty(sf),sf='boxcar';end
if ak==0,ak=zeros(1,lmax);end,ak=[a0 ak];  %Set up coefficient arrays
if bk==0,bk=zeros(1,lmax);end,bk=[0 bk];
k=[0 k];l=lmax+1;kk=[0 kk];ll=ll+1;f1=kk/T;
N=200;f0=1/T;t=0:T/N:T;  %Set up 129 point time array
c=sqrt(ak(1:ll).*ak(1:ll)+bk(1:ll).*bk(1:ll));  %Magnitude spectrum
 vx=matverch;
 if vx < 4, eval('clg');else,eval('clf');end
hold off,subplot(221)
dtplot(f1,c,'.'),title('Magnitude spectrum'),
a=1;z=zeros(4,length(t));y=ak(1)+z(1,:);y3=y;
sc=windo(sf,2*nh+1);sc=sc(nh+2:2*nh+1);sc=sc(1:d:nh);
for jj=1:d:nh
a=a+1;sm=(ak(a)*cos(2*pi*f0*jj*t)+bk(a)*sin(2*pi*f0*jj*t));
y=y+sm;y3=y3+sm*sc(a-1);
if a==2;z(4,:)=y;end,if a==3;z(3,:)=y;end,if a==4;z(2,:)=y;end
end
z(1,:)=y;mm=max(max(z));nn=min(min(z));ax=[0 T nn-0.1*abs(mm) mm+0.1*abs(mm)];
subplot(223),axis(ax);plot(t,z),axis(ax);title('Intermediate Reconstructions')
subplot(222),axis(ax);plot(t,y),axis(ax);title('Final Reconstruction')
subplot(224),axis(ax);plot(t,y3),axis(ax);title(['Smoothing: ' sf ' window'])
pause,subplot,hold off