计算七类窗函数并给出归一化对数幅频曲线
主程序：c----------------------------------------------------------------------
c main program HWINDOW: To test subroutine WINDOW
c Please link subroutine WINDOW
C----------------------------------------------------------------------
dimension w(0:127)
n=128
write(*,*)' Please input Iwindow='
write(*,*)' Note: Iwindow=1,2,...,7'
read(*,*)Iwindow
call window(w,n,iwindow,ierror)
write(*,*)' ierror=',ierror
if(ierror.ne.0) stop
open(3,file='window.dat',status='new')
do 10 k=0,n-1
write(3,*)k,w(k)
10 continue
close(3)
stop
end
子程序：
subroutine window(w,n,iwindow,ierror)
c----------------------------------------------------------------------
cRoutine WINDOW: To Obtain Window Function.
cInput parameters:
c n : the length of window data.
c iwindow: window type desired.
c if : iwindow=1: rectangular window ,=2: triangular window ,
C =3: cosin window , =4: Hanning window ,
C =5: Hamming window , =6: Blackman window ,
c =7: Papoulis window .
cOutput parameters:
c w : N dimensioned real array.the result is in w(0) to w(n-1).
C ierror:IF IERROR=0: no error, =1: Iwindow out of range.
c in chapter 8
C----------------------------------------------------------------------
dimension w(0:n-1)
ierror=1
if(iwindow.lt.1.or.iwindow.gt.7) return
ierror=0
pi=4.*atan(1.)
pn=2.*pi/float(n)
goto (1,2,3,4,5,6,7), iwindow
1 do 11 i=0,n-1
11 w(i)=1.
return
2 do 12 i=0,n-1
12 w(i)=1.-abs(1.-2.*i/float(n))
return
3 do 13 i=0,n-1
13 w(i)=sin(pn*i/2.)
return
4 do 14 i=0,n-1
14 w(i)=0.5*(1.0-cos(pn*i))
return
5 do 15 i=0,n-1
15 w(i)=0.54-0.46*cos(pn*i)
return
6 do 16 i=0,n-1
16 w(i)=0.42-0.5*cos(pn*i)+0.08*cos(2.*pn*i)
return
7 do 17 i=0,n-1
a=abs(sin(pn*i))/pi
b=1.-2.*(abs(i-n/2.))/float(n)
c=cos(pn*i)
17 w(i)=a-b*c
return
end
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