subroutine sync4(dat,jz,mode4,minw) ! Synchronizes JT4 data, finding the best-fit DT and DF. use jt4 parameter (NFFTMAX=2520) !Max length of FFTs parameter (NHMAX=NFFTMAX/2) !Max length of power spectra parameter (NSMAX=525) !Max number of half-symbol steps real dat(jz) real psavg(NHMAX) !Average spectrum of whole record real s2(NHMAX,NSMAX) !2d spectrum, stepped by half-symbols real ccfblue(65) !CCF with pseudorandom sequence real tmp(1260) save ! Do FFTs of twice symbol length, stepped by half symbols. Note that ! we have already downsampled the data by factor of 2. nsym=207 nfft=2520 nh=nfft/2 nq=nfft/4 nsteps=jz/nq - 1 df=0.5*11025.0/nfft psavg(1:nh)=0. call timer('ps4 ',0) do j=1,nsteps !Compute spectrum for each step, get average k=(j-1)*nq + 1 call ps4(dat(k),nfft,s2(1,j)) psavg(1:nh)=psavg(1:nh) + s2(1:nh,j) enddo call timer('ps4 ',1) call timer('flat1a ',0) nsmo=min(10*mode4,150) call flat1a(psavg,nsmo,s2,nh,nsteps,NHMAX,NSMAX) !Flatten spectra call timer('flat1a ',1) call timer('smo ',0) if(mode4.ge.9) call smo(psavg,nh,tmp,mode4/4) call timer('smo ',1) ia=600.0/df ib=1600.0/df ! ichmax=1.0+log(float(mode4))/log(2.0) do ich=minw+1,7 !Find best width kz=nch(ich)/2 ! Set istep>1 for wide submodes? do i=ia+kz,ib-kz !Find best frequency channel for CCF call timer('xcor4 ',0) call xcor4(s2,i,nsteps,nsym,ich,mode4) call timer('xcor4 ',1) enddo enddo return end subroutine sync4