window1d.m

介绍了傅立叶变换的基本原理

function w=window1d(p,wtype,param) 
> USAGE: w=window1d(p,wtype,param) 
> return 1-dimensional window of type 'wtype' 
> 
> centred on (p/2) 
> p = length of window 
> 
> TYPES are BARTLETT, BLACKMAN, BOXCAR, CHEBWIN, HAMMING, HANN and KAISER 
> 
> Adam Wilmer, October 2002 

w = zeros(p); 

switch lower(wtype) 
case 'none' 
w = ones(p,1); 
case 'bartlett' 
w = bartlett(p); 

case 'blackman' 
w = blackman(p); 

case 'boxcar' > same as 'none' really so don't really see the point in this one 
w = boxcar(p); 

case 'chebwin' 
if (nargin==4) 
r = param; > this is the desired sidelobe attenuation in dB 
else 
r=100; 
end 
w = chebwin(p,r); > Some 1D window 

case 'hamming' 
w = hamming(p); > Some 1D window 

case 'hann' 
w = hann(p); > Some 1D window 

case 'kaiser' 
if (nargin==4) 
beta = param; > this is the Kaiser window beta parameter 
else 
beta=10; 
end 
w = kaiser(p,beta); > Some 1D window 

case 'triang' 
w = triang(p); > Some 1D window 

otherwise 
disp('Window choice is not recognised -- choose another...') 
help window1d; 
return; 
end