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Use overlap and add to apply reference filter/amplitude equalization.

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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7893 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke 2017-07-15 15:43:41 +00:00
parent 8af95e2582
commit 86776ed0d1
1 changed files with 11 additions and 17 deletions
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28
lib/refspectrum.f90
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@ -8,10 +8,7 @@ subroutine refspectrum(id2,id2b,kk,bclear,brefspec,buseref,fname)
integer*2 id2(NFFT),id2b(120*12000)
logical*1 bclear,brefspec,buseref,blastuse
real x0(0:NH-1) !Input samples
real x1(0:NH-1) !Output samples (delayed by one block)
real x0s(0:NH-1) !Saved upper half of input samples
real x1s(0:NH-1) !Saved upper half of output samples
real xs(0:NH-1) !Saved upper half of input samples
real x(0:NFFT-1) !Work array
real*4 w(0:NFFT-1) !Window function
real*4 s(0:NH) !Average spectrum
@ -34,8 +31,7 @@ subroutine refspectrum(id2,id2b,kk,bclear,brefspec,buseref,fname)
nsave=0
s=0.0
filter=1.0
x0s=0.
x1s=0.
xs=0.
first=.false.
endif
if(bclear) s=0.
@ -137,18 +133,16 @@ subroutine refspectrum(id2,id2b,kk,bclear,brefspec,buseref,fname)
100 close(16)
110 continue
endif
x0=id2(1:NH)
x(0:NH-1)=x0s !Previous 2nd half to new 1st half
x(NH:NFFT-1)=x0 !New 2nd half
x0s=x0 !Save the new 2nd half
x=w*x !Apply window
call four2a(x,NFFT,1,-1,0) !r2c FFT (to frequency domain)
! Use overlap and add method to apply reference filter
x(0:NH-1)=id2(1:NH)
x(NH:NFFT-1)=0.0
x=x/NFFT
call four2a(x,NFFT,1,-1,0)
cx=fil*cx
call four2a(cx,NFFT,1,1,-1) !c2r FFT (back to time domain)
x1=x1s + x(0:NH-1) !Add previous segment's 2nd half
! id2(1:NH)=nint(x1)
if(kk.ge.6912) id2b(kk-6192+1:kk-6192+NH)=nint(x1)
x1s=x(NH:NFFT-1) !Save the new 2nd half
call four2a(cx,NFFT,1,1,-1)
x(0:NH-1)=x(0:NH-1)+xs
xs=x(NH:NFFT-1)
id2(1:NH)=nint(x(0:NH-1))
endif
blastuse=buseref