mirror of https://github.com/saitohirga/WSJT-X.git
60 lines
1.6 KiB
Fortran
60 lines
1.6 KiB
Fortran
subroutine sync4(dat,jz,mode4,minw)
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! Synchronizes JT4 data, finding the best-fit DT and DF.
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use jt4
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parameter (NFFTMAX=2520) !Max length of FFTs
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parameter (NHMAX=NFFTMAX/2) !Max length of power spectra
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parameter (NSMAX=525) !Max number of half-symbol steps
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real dat(jz)
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real psavg(NHMAX) !Average spectrum of whole record
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real s2(NHMAX,NSMAX) !2d spectrum, stepped by half-symbols
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real tmp(1260)
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save
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! Do FFTs of twice symbol length, stepped by half symbols. Note that
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! we have already downsampled the data by factor of 2.
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nsym=207
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nfft=2520
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nh=nfft/2
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nq=nfft/4
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nsteps=jz/nq - 1
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df=0.5*11025.0/nfft
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psavg(1:nh)=0.
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call timer('ps4 ',0)
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do j=1,nsteps !Compute spectrum for each step, get average
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k=(j-1)*nq + 1
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call ps4(dat(k),nfft,s2(1,j))
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psavg(1:nh)=psavg(1:nh) + s2(1:nh,j)
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enddo
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call timer('ps4 ',1)
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call timer('flat1a ',0)
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nsmo=min(10*mode4,150)
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call flat1a(psavg,nsmo,s2,nh,nsteps,NHMAX,NSMAX) !Flatten spectra
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call timer('flat1a ',1)
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call timer('smo ',0)
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if(mode4.ge.9) call smo(psavg,nh,tmp,mode4/4)
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call timer('smo ',1)
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ia=600.0/df
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ib=1600.0/df
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! ichmax=1.0+log(float(mode4))/log(2.0)
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do ich=minw+1,7 !Find best width
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kz=nch(ich)/2
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! Set istep>1 for wide submodes?
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do i=ia+kz,ib-kz !Find best frequency channel for CCF
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call timer('xcor4 ',0)
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call xcor4(s2,i,nsteps,nsym,ich,mode4)
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call timer('xcor4 ',1)
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enddo
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enddo
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return
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end subroutine sync4
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