mirror of https://github.com/saitohirga/WSJT-X.git
60 lines
1.3 KiB
Fortran
60 lines
1.3 KiB
Fortran
subroutine hspec(id2,k,ingain,green,s,jh)
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! Input:
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! k pointer to the most recent new data
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! Output:
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! green() power
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! s() spectrum for horizontal spectrogram
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! jh index of most recent data in green(), s()
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parameter (JZ=703)
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integer*2 id2(0:120*12000-1)
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real green(0:JZ-1)
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real s(0:63,0:JZ-1)
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real x(512)
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complex cx(0:256)
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data rms/999.0/,k0/99999999/
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equivalence (x,cx)
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save ja,rms0
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gain=10.0**(0.1*ingain)
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nfft=512
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if(k.gt.30*12000) go to 900
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if(k.lt.nfft) then
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jh=0
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go to 900 !Wait for enough samples to start
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endif
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if(k.lt.k0) then !Start a new data block
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ja=0
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jh=-1
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rms0=0.0
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endif
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do iblk=1,7
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if(jh.lt.JZ-1) jh=jh+1
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jb=ja+nfft-1
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x=id2(ja:jb)
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sq=dot_product(x,x)
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rms=sqrt(gain*sq/nfft)
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green(jh)=0.
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if(rms.gt.0.0) green(jh)=20.0*log10(0.5*(rms0+rms))
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rms0=rms
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call four2a(x,nfft,1,-1,0) !Real-to-complex FFT
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df=12000.0/nfft
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fac=(1.0/nfft)**2
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do i=1,64
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j=2*i
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sx=real(cx(j))**2 + aimag(cx(j))**2 + real(cx(j-1))**2 + &
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aimag(cx(j-1))**2
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s(i-1,jh)=fac*gain*sx
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enddo
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if(ja+2*nfft.gt.k) exit
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ja=ja+nfft
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enddo
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k0=k
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900 return
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end subroutine hspec
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