2005-12-22 11:40:53 -05:00
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subroutine spec441(dat,jz,s,f0)
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C Computes average spectrum over a range of dat, e.g. for a ping.
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C Returns spectral array and frequency of peak value.
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parameter (NFFT=256)
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parameter (NR=NFFT+2)
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parameter (NH=NFFT/2)
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real*4 dat(jz)
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real*4 x(NR),s(NH)
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complex c(0:NH)
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equivalence (x,c)
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call zero(s,NH)
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nz=jz/NFFT
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do n=1,nz
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j=1 + (n-1)*NFFT
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call move(dat(j),x,NFFT)
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call xfft(x,NFFT)
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do i=1,NH
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2006-04-05 16:07:32 -04:00
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s(i)=s(i)+real(c(i))**2 + aimag(c(i))**2
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2005-12-22 11:40:53 -05:00
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enddo
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enddo
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smax=0.
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df=11025.0/NFFT
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fac=1.0/(100.0*nfft*nz)
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do i=1,nh
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s(i)=fac*s(i)
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if(s(i).gt.smax) then
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smax=s(i)
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f0=i*df
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endif
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enddo
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return
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end
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