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			474 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Fortran
		
	
	
	
	
	
			
		
		
	
	
			474 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			Fortran
		
	
	
	
	
	
| program ft4sd
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| 
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| ! Decode ft4slow data read from *.c2 or *.wav files.
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| 
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|    use packjt77
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|    include 'ft4s_params.f90'
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|    parameter (NSPS2=NSPS/32)
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|    character arg*8,cbits*50,infile*80,fname*16,datetime*11
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|    character ch1*1,ch4*4,cseq*31
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|    character*22 decodes(100)
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|    character*37 msg
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|    character*120 data_dir
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|    character*77 c77
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|    complex c2(0:NMAX/32-1)              !Complex waveform
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|    complex cframe(0:144*NSPS2-1)               !Complex waveform
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|    complex cd(0:144*20-1)                   !Complex waveform
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|    real*8 fMHz
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|    real llr(240),llra(240),llrb(240),llrc(240),llrd(240)
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|    real candidates(100,2)
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|    real bitmetrics(288,4)
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|    integer ihdr(11)
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|    integer*2 iwave(NMAX)                 !Generated full-length waveform
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|    integer*1 apmask(240),cw(240)
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|    integer*1 hbits(288)
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|    integer*1 message101(101)
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|    logical badsync,unpk77_success
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| 
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|    fs=12000.0/NDOWN                       !Sample rate
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|    dt=1.0/fs                              !Sample interval (s)
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|    tt=NSPS*dt                             !Duration of "itone" symbols (s)
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|    txt=NZ*dt                              !Transmission length (s)
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|    hmod=1.0
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|    Keff=91
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| 
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|    nargs=iargc()
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|    if(nargs.lt.1) then
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|       print*,'Usage:   ft4sd [-a <data_dir>] [-f fMHz] [-h hmod] [-k Keff] file1 [file2 ...]'
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|       go to 999
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|    endif
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|    iarg=1
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|    data_dir="."
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|    call getarg(iarg,arg)
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|    if(arg(1:2).eq.'-a') then
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|       call getarg(iarg+1,data_dir)
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|       iarg=iarg+2
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|       call getarg(iarg,arg)
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|    endif
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|    if(arg(1:2).eq.'-f') then
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|       call getarg(iarg+1,arg)
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|       read(arg,*) fMHz
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|       iarg=iarg+2
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|       call getarg(iarg,arg)
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|    endif
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|    if(arg(1:2).eq.'-h') then
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|       call getarg(iarg+1,arg)
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|       read(arg,*) hmod 
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|       iarg=iarg+2
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|       call getarg(iarg,arg)
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|    endif
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|    if(arg(1:2).eq.'-k') then
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|       call getarg(iarg+1,arg)
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|       read(arg,*) Keff 
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|       iarg=iarg+2
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|    endif
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| 
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|    ngood=0
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|    do ifile=iarg,nargs
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|       call getarg(ifile,infile)
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|       open(10,file=infile,status='old',access='stream')
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|       j1=index(infile,'.c2')
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|       j2=index(infile,'.wav')
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|       if(j1.gt.0) then
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|          read(10,end=999) fname,ntrmin,fMHz,c2
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|          read(fname(8:11),*) nutc
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|          write(datetime,'(i11)') nutc
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|       else if(j2.gt.0) then
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|          read(10,end=999) ihdr,iwave
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|          read(infile(j2-4:j2-1),*) nutc
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|          datetime=infile(j2-11:j2-1)
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|          call ft4s_downsample(iwave,c2)
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|       else
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|          print*,'Wrong file format?'
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|          go to 999
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|       endif
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|       close(10)
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| 
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|       fa=-100.0
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|       fb=100.0
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|       fs=12000.0/32.0
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|       npts=120*12000.0/32.0
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| 
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|       call getcandidate_ft4s(c2,npts,hmod,fs,fa,fb,ncand,candidates)         !First approx for freq
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| 
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|       del=1.5*hmod*fs/300.0
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|       ndecodes=0
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|       do icand=1,ncand
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|          fc0=candidates(icand,1)
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|          xsnr=candidates(icand,2)
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| !write(*,*) 'candidates ',icand,fc0,xsnr
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|          do isync=0,1
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| 
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|             if(isync.eq.0) then
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|                fc1=fc0-del
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|                is0=375
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|                ishw=350
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|                isst=30
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|                ifhw=10
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|                df=.1
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|             else if(isync.eq.1) then
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|                fc1=fc2
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|                is0=isbest
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|                ishw=100
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|                isst=10
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|                ifhw=10
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|                df=.02
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|             endif
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|             smax=0.0
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|             do if=-ifhw,ifhw
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|                fc=fc1+df*if
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|                do istart=max(1,is0-ishw),is0+ishw,isst
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|                   call coherent_sync_ft4s(c2,istart,hmod,fc,1,sync)
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|                   if(sync.gt.smax) then
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|                      fc2=fc
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|                      isbest=istart
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|                      smax=sync
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|                   endif
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|                enddo
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|             enddo
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| !            write(*,*) ifile,icand,isync,fc1+del,fc2+del,isbest,smax
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|          enddo
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| 
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| !         if(smax .lt. 100.0 ) cycle
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| !isbest=375
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| !fc2=-del
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|          do ijitter=0,2
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|             if(ijitter.eq.0) ioffset=0
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|             if(ijitter.eq.1) ioffset=45
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|             if(ijitter.eq.2) ioffset=-45
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|             is0=isbest+ioffset
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|             if(is0.lt.0) cycle
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|             cframe=c2(is0:is0+144*300-1)
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|             call downsample_ft4s(cframe,fc2+del,hmod,cd)
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|             s2=sum(cd*conjg(cd))/(20*144)
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|             cd=cd/sqrt(s2)
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|             call get_ft4s_bitmetrics(cd,hmod,bitmetrics,badsync)
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| 
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|             hbits=0
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|             where(bitmetrics(:,1).ge.0) hbits=1
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|             ns1=count(hbits(  1:  8).eq.(/0,0,0,1,1,0,1,1/))
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|             ns2=count(hbits( 57: 64).eq.(/0,1,0,0,1,1,1,0/))
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|             ns3=count(hbits(113:120).eq.(/1,1,1,0,0,1,0,0/))
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|             ns4=count(hbits(169:176).eq.(/1,0,1,1,0,0,0,1/))
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|             ns5=count(hbits(225:232).eq.(/0,0,1,1,1,0,0,1/))
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|             ns6=count(hbits(281:288).eq.(/0,1,1,1,0,0,1,0/))
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|             nsync_qual=ns1+ns2+ns3+ns4+ns5+ns6
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| !          if(nsync_qual.lt. 20) cycle
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| 
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|             scalefac=2.83
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|             llra(  1: 48)=bitmetrics(  9: 56, 1)
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|             llra( 49: 96)=bitmetrics( 65:112, 1)
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|             llra( 97:144)=bitmetrics(121:168, 1)
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|             llra(145:192)=bitmetrics(177:224, 1)
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|             llra(193:240)=bitmetrics(233:280, 1)
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|             llra=scalefac*llra
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|             llrb(  1: 48)=bitmetrics(  9: 56, 2)
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|             llrb( 49: 96)=bitmetrics( 65:112, 2)
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|             llrb( 97:144)=bitmetrics(121:168, 2)
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|             llrb(145:192)=bitmetrics(177:224, 2)
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|             llrb(193:240)=bitmetrics(233:280, 2)
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|             llrb=scalefac*llrb
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|             llrc(  1: 48)=bitmetrics(  9: 56, 3)
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|             llrc( 49: 96)=bitmetrics( 65:112, 3)
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|             llrc( 97:144)=bitmetrics(121:168, 3)
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|             llrc(145:192)=bitmetrics(177:224, 3)
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|             llrc(193:240)=bitmetrics(233:280, 3)
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|             llrc=scalefac*llrc
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|             llrd(  1: 48)=bitmetrics(  9: 56, 4)
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|             llrd( 49: 96)=bitmetrics( 65:112, 4)
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|             llrd( 97:144)=bitmetrics(121:168, 4)
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|             llrd(145:192)=bitmetrics(177:224, 4)
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|             llrd(193:240)=bitmetrics(233:280, 4)
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|             llrd=scalefac*llrd
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|             apmask=0
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|             max_iterations=40
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| 
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|             do itry=4,1,-1
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|                if(itry.eq.1) llr=llra
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|                if(itry.eq.2) llr=llrb
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|                if(itry.eq.3) llr=llrc
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|                if(itry.eq.4) llr=llrd
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|                nhardbp=0
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|                nhardosd=0
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|                dmin=0.0
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|                call bpdecode240_101(llr,apmask,max_iterations,message101,cw,nhardbp,niterations,nchecks)
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| !               if(nhardbp.lt.0) call osd240_101(llr,Keff,apmask,5,message101,cw,nhardosd,dmin)
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|                maxsuperits=2
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|                ndeep=3  ! use ndeep=3 with Keff=91
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|                if(Keff.eq.77) ndeep=4
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|                if(nhardbp.lt.0) then
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| !                  call osd240_101(llr,Keff,apmask,ndeep,message101,cw,nhardosd,dmin)
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|                   call decode240_101(llr,Keff,ndeep,apmask,maxsuperits,message101,cw,nhardosd,iter,ncheck,dmin,isuper)
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|                endif
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|                if(nhardbp.ge.0 .or. nhardosd.ge.0) then
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|                   write(c77,'(77i1)') message101(1:77)
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|                   call unpack77(c77,0,msg,unpk77_success)
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|                   if(unpk77_success .and. index(msg,'K9AN').gt.0) then
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|                      ngood=ngood+1
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|                      write(*,1100) ifile-2,icand,xsnr,isbest/375.0-1.0,1500.0+fc2+del,msg(1:20),itry,nhardbp,nhardosd,dmin,ijitter
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| 1100                 format(i5,2x,i5,2x,f6.1,2x,f6.2,2x,f8.2,2x,a20,i4,i4,i4,f7.2,i6)
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|                      goto 2002 
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|                   else
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|                      cycle
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|                   endif
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|                endif
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|             enddo  ! metrics
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|          enddo  ! istart jitter
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|       enddo !candidate list
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| 2002  continue
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|    enddo !files
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|    nfiles=nargs-iarg+1
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|    write(*,*) 'nfiles: ',nfiles,' ngood: ',ngood
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|    write(*,1120)
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| 1120 format("<DecodeFinished>")
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| 
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| 999 end program ft4sd
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| 
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| subroutine coherent_sync_ft4s(cd0,i0,hmod,f0,itwk,sync)
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| 
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| ! Compute sync power for a complex, downsampled FT4s signal.
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| 
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|    include 'ft4s_params.f90'
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|    parameter(NP=NMAX/NDOWN,NSS=NSPS/NDOWN)
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|    complex cd0(0:NP-1)
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|    complex csynca(4*NSS),csyncb(4*NSS)
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|    complex csyncc(4*NSS),csyncd(4*NSS)
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|    complex csynce(4*NSS),csyncf(4*NSS)
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|    complex csync2(4*NSS)
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|    complex ctwk(4*NSS)
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|    complex z1,z2,z3,z4,z5,z6
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|    logical first
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|    integer icos4a(0:3),icos4b(0:3)
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|    integer icos4c(0:3),icos4d(0:3)
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|    integer icos4e(0:3),icos4f(0:3)
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|    data icos4a/0,1,3,2/
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|    data icos4b/1,0,2,3/
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|    data icos4c/2,3,1,0/
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|    data icos4d/3,2,0,1/
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|    data icos4e/0,2,3,1/
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|    data icos4f/1,2,0,3/
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|    data first/.true./
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|    save first,twopi,csynca,csyncb,csyncc,csyncd,csynce,csyncf,fac
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| 
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|    p(z1)=(real(z1*fac)**2 + aimag(z1*fac)**2)**0.5          !Statement function for power
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| 
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|    if( first ) then
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|       twopi=8.0*atan(1.0)
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|       k=1
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|       phia=0.0
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|       phib=0.0
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|       phic=0.0
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|       phid=0.0
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|       phie=0.0
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|       phif=0.0
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|       do i=0,3
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|          dphia=twopi*hmod*icos4a(i)/real(NSS)
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|          dphib=twopi*hmod*icos4b(i)/real(NSS)
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|          dphic=twopi*hmod*icos4c(i)/real(NSS)
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|          dphid=twopi*hmod*icos4d(i)/real(NSS)
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|          dphie=twopi*hmod*icos4e(i)/real(NSS)
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|          dphif=twopi*hmod*icos4f(i)/real(NSS)
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|          do j=1,NSS
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|             csynca(k)=cmplx(cos(phia),sin(phia))
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|             csyncb(k)=cmplx(cos(phib),sin(phib))
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|             csyncc(k)=cmplx(cos(phic),sin(phic))
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|             csyncd(k)=cmplx(cos(phid),sin(phid))
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|             csynce(k)=cmplx(cos(phie),sin(phie))
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|             csyncf(k)=cmplx(cos(phif),sin(phif))
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|             phia=mod(phia+dphia,twopi)
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|             phib=mod(phib+dphib,twopi)
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|             phic=mod(phic+dphic,twopi)
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|             phid=mod(phid+dphid,twopi)
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|             phie=mod(phie+dphie,twopi)
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|             phif=mod(phif+dphif,twopi)
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|             k=k+1
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|          enddo
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|       enddo
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|       first=.false.
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|       fac=1.0/(4.0*NSS)
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|    endif
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| 
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|    i1=i0                            !four Costas arrays
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|    i2=i0+28*NSS
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|    i3=i0+56*NSS
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|    i4=i0+84*NSS
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|    i5=i0+112*NSS
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|    i6=i0+140*NSS
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| 
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|    z1=0.
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|    z2=0.
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|    z3=0.
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|    z4=0.
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|    z5=0.
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|    z6=0.
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| 
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|    if(itwk.eq.1) then
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|       dt=1/(12000.0/32.0)
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|       dphi=twopi*f0*dt
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|       phi=0.0
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|       do i=1,4*NSS
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|          ctwk(i)=cmplx(cos(phi),sin(phi))
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|          phi=mod(phi+dphi,twopi)
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|       enddo
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|    endif
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| 
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|    if(itwk.eq.1) csync2=ctwk*csynca      !Tweak the frequency
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|    if(i1.ge.0 .and. i1+4*NSS-1.le.NP-1) then
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|       z1=sum(cd0(i1:i1+4*NSS-1)*conjg(csync2))
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|    elseif( i1.lt.0 ) then
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|       npts=(i1+4*NSS-1)/2
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|       if(npts.le.40) then
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|          z1=0.
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|       else
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|          z1=sum(cd0(0:i1+4*NSS-1)*conjg(csync2(4*NSS-npts:)))
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|       endif
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|    endif
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| 
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|    if(itwk.eq.1) csync2=ctwk*csyncb      !Tweak the frequency
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|    if(i2.ge.0 .and. i2+4*NSS-1.le.NP-1) then
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|       z2=sum(cd0(i2:i2+4*NSS-1)*conjg(csync2))
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|    endif
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| 
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|    if(itwk.eq.1) csync2=ctwk*csyncc      !Tweak the frequency
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|    if(i3.ge.0 .and. i3+4*NSS-1.le.NP-1) then
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|       z3=sum(cd0(i3:i3+4*NSS-1)*conjg(csync2))
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|    endif
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| 
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|    if(itwk.eq.1) csync2=ctwk*csyncd      !Tweak the frequency
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|    if(i4.ge.0 .and. i4+4*NSS-1.le.NP-1) then
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|       z4=sum(cd0(i4:i4+4*NSS-1)*conjg(csync2))
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|    endif
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| 
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|    if(itwk.eq.1) csync2=ctwk*csynce      !Tweak the frequency
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|    if(i5.ge.0 .and. i5+4*NSS-1.le.NP-1) then
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|       z5=sum(cd0(i5:i5+4*NSS-1)*conjg(csync2))
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|    endif
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| 
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|    if(itwk.eq.1) csync2=ctwk*csyncf      !Tweak the frequency
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|    if(i6.ge.0 .and. i6+4*NSS-1.le.NP-1) then
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|       z6=sum(cd0(i6:i6+4*NSS-1)*conjg(csync2))
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|    elseif( i6+4*NSS-1.gt.NP-1 ) then
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|       npts=(NP-1-i6+1)
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|       if(npts.le.40) then
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|          z6=0.
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|       else
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|          z6=sum(cd0(i6:i6+npts-1)*conjg(csync2(1:npts)))
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|       endif
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|    endif
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| 
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|    sync = p(z1) + p(z2) + p(z3) + p(z4) + p(z5) + p(z6)
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| 
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|    return
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| end subroutine coherent_sync_ft4s
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| 
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| subroutine downsample_ft4s(ci,f0,hmod,co)
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|    parameter(NI=144*300,NH=NI/2,NO=NI/15)  ! downsample from 315 samples per symbol to 20 
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|    complex ci(0:NI-1),ct(0:NI-1)
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|    complex co(0:NO-1)
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|    fs=12000.0/32.0
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|    df=fs/NI
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|    ct=ci
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|    call four2a(ct,NI,1,-1,1)             !c2c FFT to freq domain
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|    i0=nint(f0/df)
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|    ct=cshift(ct,i0)
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|    co=0.0
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|    co(0)=ct(0)
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|    b=16.0*hmod
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|    do i=1,NO/2
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|       arg=(i*df/b)**2
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|       filt=exp(-arg)
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|       co(i)=ct(i)*filt
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|       co(NO-i)=ct(NI-i)*filt
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|    enddo
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|    co=co/NO
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|    call four2a(co,NO,1,1,1)            !c2c FFT back to time domain
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|    return
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| end subroutine downsample_ft4s
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| 
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| subroutine getcandidate_ft4s(c,npts,hmod,fs,fa,fb,ncand,candidates)
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|    parameter(NFFT1=120*12000/32,NH1=NFFT1/2,NFFT2=120*12000/320,NH2=NFFT2/2)
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|    complex c(0:npts-1)                   !Complex waveform
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|    complex cc(0:NFFT1-1)
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|    complex csfil(0:NFFT2-1)
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|    complex cwork(0:NFFT2-1)
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|    real bigspec(0:NFFT2-1)
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|    complex c2(0:NFFT1-1)                 !Short spectra
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|    real s(-NH1+1:NH1)                    !Coarse spectrum
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|    real ss(-NH1+1:NH1)                   !Smoothed coarse spectrum
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|    real candidates(100,2)
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|    integer indx(NFFT2-1)
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|    logical first
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|    data first/.true./
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|    save first,w,df,csfil
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| 
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|    if(first) then
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|       df=10*fs/NFFT1
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|       csfil=cmplx(0.0,0.0)
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|       do i=0,NFFT2-1
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| !         csfil(i)=exp(-((i-NH2)/32.0)**2)  ! revisit this
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|          csfil(i)=exp(-((i-NH2)/(hmod*28.0))**2)  ! revisit this
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|       enddo
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|       csfil=cshift(csfil,NH2)
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|       call four2a(csfil,NFFT2,1,-1,1)
 | |
|       first=.false.
 | |
|    endif
 | |
| 
 | |
|    cc=cmplx(0.0,0.0)
 | |
|    cc(0:npts-1)=c;
 | |
|    call four2a(cc,NFFT1,1,-1,1)
 | |
|    cc=abs(cc)**2
 | |
|    call four2a(cc,NFFT1,1,-1,1)
 | |
|    cwork(0:NH2)=cc(0:NH2)*conjg(csfil(0:NH2))
 | |
|    cwork(NH2+1:NFFT2-1)=cc(NFFT1-NH2+1:NFFT1-1)*conjg(csfil(NH2+1:NFFT2-1))
 | |
| 
 | |
|    call four2a(cwork,NFFT2,1,+1,1)
 | |
|    bigspec=cshift(real(cwork),-NH2)
 | |
|    il=NH2+fa/df
 | |
|    ih=NH2+fb/df
 | |
|    nnl=ih-il+1
 | |
|    call indexx(bigspec(il:il+nnl-1),nnl,indx)
 | |
|    xn=bigspec(il-1+indx(nint(0.3*nnl)))
 | |
|    bigspec=bigspec/xn
 | |
|    ncand=0
 | |
|    do i=il,ih
 | |
|       if((bigspec(i).gt.bigspec(i-1)).and. &
 | |
|          (bigspec(i).gt.bigspec(i+1)).and. &
 | |
|          (bigspec(i).gt.1.15).and.ncand.lt.100) then
 | |
|          ncand=ncand+1
 | |
|          candidates(ncand,1)=df*(i-NH2)
 | |
|          candidates(ncand,2)=10*log10(bigspec(i)-1)-26.5
 | |
|       endif
 | |
|    enddo
 | |
|    return
 | |
| end subroutine getcandidate_ft4s
 | |
| 
 | |
| subroutine ft4s_downsample(iwave,c)
 | |
| 
 | |
| ! Input: i*2 data in iwave() at sample rate 12000 Hz
 | |
| ! Output: Complex data in c(), sampled at 375 Hz
 | |
| 
 | |
|    include 'ft4s_params.f90'
 | |
|    parameter (NFFT2=NMAX/32)
 | |
|    integer*2 iwave(NMAX)
 | |
|    complex c(0:NMAX/32-1)
 | |
|    complex c1(0:NFFT2-1)
 | |
|    complex cx(0:NMAX/2)
 | |
|    real x(NMAX)
 | |
|    equivalence (x,cx)
 | |
| 
 | |
|    df=12000.0/NMAX
 | |
|    x=iwave
 | |
|    call four2a(x,NMAX,1,-1,0)             !r2c FFT to freq domain
 | |
|    i0=nint(1500.0/df)
 | |
|    c1(0)=cx(i0)
 | |
|    do i=1,NFFT2/2
 | |
|       c1(i)=cx(i0+i)
 | |
|       c1(NFFT2-i)=cx(i0-i)
 | |
|    enddo
 | |
|    c1=c1/NFFT2
 | |
|    call four2a(c1,NFFT2,1,1,1)            !c2c FFT back to time domain
 | |
|    c=c1(0:NMAX/32-1)
 | |
|    return
 | |
| end subroutine ft4s_downsample
 | |
| 
 |