545 lines
15 KiB
Plaintext
545 lines
15 KiB
Plaintext
program wspr5d
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! Decode WSPR-LF data read from *.c5 or *.wav files.
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! WSPR-LF is a potential WSPR-like mode intended for use at LF and MF.
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! It uses an LDPC (300,60) code, OQPSK modulation, and 5 minute T/R sequences.
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!
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! Still to do: find and decode more than one signal in the specified passband.
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! include 'wsprlf_params.f90'
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parameter (NDOWN=30)
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parameter (KK=60)
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parameter (ND=300)
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parameter (NS=109)
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parameter (NR=3)
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parameter (NN=NR+NS+ND)
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parameter (NSPS0=8640)
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parameter (NSPS=16)
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parameter (N2=2*NSPS)
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parameter (NZ=NSPS*NN)
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parameter (NZ400=288*NN)
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parameter (NMAX=300*12000)
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character arg*8,message*22,cbits*50,infile*80,fname*16,datetime*11
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character*120 data_dir
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complex csync(0:NZ-1) !Sync symbols only, from cbb
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complex c400(0:NZ400-1) !Complex waveform
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complex c(0:NZ-1) !Complex waveform
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complex cd(0:NZ-1) !Complex waveform
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complex ca(0:NZ-1) !Complex waveform
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complex zz,zzsum
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real*8 fMHz
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real rxdata(ND),llr(ND) !Soft symbols
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real pp(32) !Shaped pulse for OQPSK
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real sbits(412),softbits(9)
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real fpks(20)
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integer id(NS+ND) !NRZ values (+/-1) for Sync and Data
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integer isync(48) !Long sync vector
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integer ib13(13) !Barker 13 code
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integer ihdr(11)
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integer*8 n8
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integer*2 iwave(NMAX) !Generated full-length waveform
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integer*1 idat(7)
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integer*1 decoded(KK),apmask(ND),cw(ND)
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integer*1 hbits(412),bits(13)
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logical reset
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data ib13/1,1,1,1,1,-1,-1,1,1,-1,1,-1,1/
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nargs=iargc()
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if(nargs.lt.2) then
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print*,'Usage: wspr5d [-a <data_dir>] [-f fMHz] 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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endif
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call getarg(iarg,arg)
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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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endif
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open(13,file=trim(data_dir)//'/ALL_WSPR.TXT',status='unknown', &
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position='append')
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maxn=8 !Default value
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twopi=8.0*atan(1.0)
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fs=NSPS*12000.0/NSPS0 !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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ts=2*NSPS*dt !Duration of OQPSK symbols (s)
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baud=1.0/tt !Keying rate for "itone" symbols (baud)
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txt=NZ*dt !Transmission length (s)
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do i=1,32 !Half-sine pulse shape
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pp(i)=sin(0.5*(i-1)*twopi/(32))
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enddo
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n8=z'cbf089223a51'
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do i=1,48
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isync(i)=-1
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if(iand(n8,1).eq.1) isync(i)=1
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n8=n8/2
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enddo
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! Define array id() for sync symbols
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id=0
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do j=1,48 !First group of 48
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id(2*j-1)=2*isync(j)
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enddo
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do j=1,13 !Barker 13 code
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id(j+96)=2*ib13(j)
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enddo
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do j=1,48 !Second group of 48
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id(2*j+109)=2*isync(j)
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enddo
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csync=0.
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do j=1,205
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if(abs(id(j)).eq.2) then
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ia=nint((j-0.5)*N2)
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ib=ia+N2-1
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csync(ia:ib)=pp*id(j)/abs(id(j))
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endif
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enddo
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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,'.c5')
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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,c400
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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 wspr5_downsample(iwave,c400)
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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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fa=100.0
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fb=150.0
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fs400=400.0
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call getfc1(c400,fs400,fa,fb,fc1,xsnr) !First approx for freq
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npeaks=5
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call getfc2(c400,npeaks,fs400,fc1,fpks) !Refined freq
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! do idf=1,npeaks ! consider the top npeak peaks
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do idf=1,1 ! for genie-aided sync
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fc1=125.0 ! genie provided
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fc2=0.0 ! from the genie
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! fc2=fpks(idf)
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call downsample(c400,fc1+fc2,cd)
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s2=sum(cd*conjg(cd))/(16*412)
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cd=cd/sqrt(s2)
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do is=0,0 ! dt search range is zeroed for genie-aided sync
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idt=is/2
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if( mod(is,2).eq. 1 ) idt=-(is+1)/2
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xdt=real(22+idt)/22.222 - 1.0
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ca=cshift(cd,22+idt)
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zzsum=0.0
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do iseq=3,4
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if(iseq.eq.4) then
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k=1-2*3
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nseq=9
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istep=3*4
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else
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k=1-2*iseq
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nseq=iseq*3
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istep=iseq*4
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endif
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do i=1,408,istep
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j=(i+1)*16
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if(iseq.eq.4) then
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! phase=-1.18596900
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! For now, average complex corr. coeffs over the entire frame to
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! estimate phase
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phase=atan2(imag(zzsum),real(zzsum))
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k=k+3*2
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call mskcohdet(nseq,ca(j),pp,id(k),softbits,phase)
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else
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k=k+iseq*2
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call mskseqdet(nseq,ca(j),pp,id(k),softbits,1,zz)
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zzsum=zzsum+zz
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endif
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sbits(i+1)=softbits(1)
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sbits(i+2)=softbits(2)
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if( id(k+1) .ne. 0 ) sbits(i+2)=id(k+1)*25
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sbits(i+3)=softbits(3)
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if( iseq .ge. 2 ) then
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sbits(i+5)=softbits(4)
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sbits(i+6)=softbits(5)
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if( id(k+3) .ne. 0 ) sbits(i+6)=id(k+3)*25
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sbits(i+7)=softbits(6)
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if( iseq .ge. 3 ) then
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sbits(i+9)=softbits(7)
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sbits(i+10)=softbits(8)
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if( id(k+5) .ne. 0 ) sbits(i+10)=id(k+5)*25
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sbits(i+11)=softbits(9)
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endif
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endif
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enddo
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j=1
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do i=1,205
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if( abs(id(i)) .ne. 2 ) then
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rxdata(j)=sbits(2*i-1)
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j=j+1
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endif
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enddo
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do i=1,204
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rxdata(j)=sbits(2*i)
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j=j+1
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enddo
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rxav=sum(rxdata)/ND
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rx2av=sum(rxdata*rxdata)/ND
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rxsig=sqrt(rx2av-rxav*rxav)
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rxdata=rxdata/rxsig
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sigma=1.20
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llr=2*rxdata/(sigma*sigma)
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apmask=0
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max_iterations=40
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ifer=0
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call bpdecode300(llr,apmask,max_iterations,decoded,niterations,cw)
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! niterations will be equal to the Hamming distance between hard received word and the codeword
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nhardmin=0
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if(niterations.lt.0) call osd300(llr,apmask,5,decoded,cw,nhardmin,dmin)
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if(nhardmin.gt.0) niterations=nhardmin
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nbadcrc=0
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call chkcrc10(decoded,nbadcrc)
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if(nbadcrc.ne.0) ifer=1
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if( ifer.eq.0 ) then
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write(cbits,1200) decoded(1:50)
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1200 format(50i1)
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read(cbits,1202) idat
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1202 format(6b8,b2)
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idat(7)=ishft(idat(7),6)
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call wqdecode(idat,message,itype)
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nsnr=nint(xsnr)
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! freq=fMHz + 1.d-6*(fc1+fc2)
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freq=fc1+fc2
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nfdot=0
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write(13,1210) datetime,0,nsnr,xdt,freq,message,nfdot
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1210 format(a11,2i4,f6.2,f12.7,2x,a22,i3)
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write(*,1212) datetime(8:11),nsnr,xdt,freq,nfdot,message,'*',idf,nseq,is,iseq,niterations
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!1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1,i3,i3,i3,i4)
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1212 format(a4,i4,f8.3,f8.3,i3,2x,a22,a1,i3,i3,i3,i3,i4)
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goto 888
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endif
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enddo !iseq
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enddo
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enddo
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888 continue
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enddo
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write(*,1120)
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1120 format("<DecodeFinished>")
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999 end program wspr5d
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subroutine getmetric(ib,ps,xmet)
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real ps(0:511)
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xm1=0
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xm0=0
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do i=0,511
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if( iand(i/ib,1) .eq. 1 .and. ps(i) .gt. xm1 ) xm1=ps(i)
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if( iand(i/ib,1) .eq. 0 .and. ps(i) .gt. xm0 ) xm0=ps(i)
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enddo
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xmet=xm1-xm0
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return
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end subroutine getmetric
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subroutine mskseqdet(ns,cdat,pp,bsync,softbits,ncoh,zz)
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!
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! Detect sequences of 3, 6, or 9 bits (ns).
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! Sync bits are assumed to be known.
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!
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complex cdat(16*12),cbest(16*12),cideal(16*12)
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complex cdf(16*12),cfac,zz
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real cm(0:511),cmbest(0:511)
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real pp(32),softbits(9)
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integer bit(13),bestbits(13),sgn(13)
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integer bsync(7)
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twopi=8.0*atan(1.0)
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dt=30.0*18.0/12000.0
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cmax=0;
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fbest=0.0;
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np=2**ns-1
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idfmax=40
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if( ncoh .eq. 1 ) idfmax=0
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do idf=0,idfmax
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if( mod(idf,2).eq.0 ) deltaf=idf/2*0.02
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if( mod(idf,2).eq.1 ) deltaf=-(idf+1)/2*0.02
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dphi=twopi*deltaf*dt
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cfac=cmplx(cos(dphi),sin(dphi))
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cdf=1.0
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do i=2,16*(ns-1)
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cdf(i)=cdf(i-1)*cfac
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enddo
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cm=0
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ibflag=0
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do i=0,np
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bit(1)=(bsync(1)+2)/4
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bit(2)=iand(i/(2**(ns-1)),1)
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bit(3)=iand(i/(2**(ns-2)),1)
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if( bsync(2).ne.0 ) then ! force the barker bits
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bit(3)=(bsync(2)+2)/4
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endif
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bit(4)=iand(i/(2**(ns-3)),1)
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bit(5)=(bsync(3)+2)/4
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if( ns .ge. 6 ) then
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bit(6)=iand(i/(2**(ns-4)),1)
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bit(7)=iand(i/(2**(ns-5)),1)
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if( bsync(4).ne.0 ) then ! force the barker bits
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bit(7)=(bsync(4)+2)/4
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endif
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bit(8)=iand(i/(2**(ns-6)),1)
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bit(9)=(bsync(5)+2)/4
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if( ns .eq. 9 ) then
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bit(10)=iand(i/4,1)
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bit(11)=iand(i/2,1)
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if( bsync(6).ne.0 ) then ! force the barker bits
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bit(11)=(bsync(6)+2)/4
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endif
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bit(12)=iand(i/1,1)
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bit(13)=(bsync(7)+2)/4
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endif
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endif
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sgn=2*bit-1
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cideal(1:16) =cmplx(sgn(1)*pp(17:32),sgn(2)*pp(1:16))
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cideal(17:32) =cmplx(sgn(3)*pp(1:16),sgn(2)*pp(17:32))
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cideal(33:48) =cmplx(sgn(3)*pp(17:32),sgn(4)*pp(1:16))
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cideal(49:64) =cmplx(sgn(5)*pp(1:16),sgn(4)*pp(17:32))
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if( ns .ge. 6 ) then
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cideal(65:80) =cmplx(sgn(5)*pp(17:32),sgn(6)*pp(1:16))
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cideal(81:96) =cmplx(sgn(7)*pp(1:16),sgn(6)*pp(17:32))
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cideal(97:112) =cmplx(sgn(7)*pp(17:32),sgn(8)*pp(1:16))
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cideal(113:128)=cmplx(sgn(9)*pp(1:16),sgn(8)*pp(17:32))
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if( ns .eq. 9 ) then
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cideal(129:144) =cmplx(sgn(9)*pp(17:32),sgn(10)*pp(1:16))
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cideal(145:160) =cmplx(sgn(11)*pp(1:16),sgn(10)*pp(17:32))
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cideal(161:176) =cmplx(sgn(11)*pp(17:32),sgn(12)*pp(1:16))
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cideal(177:192)=cmplx(sgn(13)*pp(1:16),sgn(12)*pp(17:32))
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endif
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endif
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cideal=cideal*cdf
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cm(i)=abs(sum(cdat(1:64*ns/3)*conjg(cideal(1:64*ns/3))))/1.e3
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if( cm(i) .gt. cmax ) then
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ibflag=1
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cmax=cm(i)
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bestbits=bit
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cbest=cideal
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fbest=deltaf
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zz=sum(cdat*conjg(cbest))/1.e3
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endif
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enddo
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if( ibflag .eq. 1 ) then ! new best found
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cmbest=cm
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endif
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enddo
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softbits=0.0
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call getmetric(1,cmbest,softbits(ns))
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call getmetric(2,cmbest,softbits(ns-1))
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call getmetric(4,cmbest,softbits(ns-2))
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if( ns .ge. 6 ) then
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call getmetric(8,cmbest,softbits(ns-3))
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call getmetric(16,cmbest,softbits(ns-4))
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call getmetric(32,cmbest,softbits(ns-5))
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if( ns .eq. 9 ) then
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call getmetric(64,cmbest,softbits(3))
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call getmetric(128,cmbest,softbits(2))
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call getmetric(256,cmbest,softbits(1))
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endif
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endif
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end subroutine mskseqdet
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subroutine mskcohdet(ns,cdat,pp,bsync,softbits,phase)
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!
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! Coherent demodulate blocks of 9 bits (ns).
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!
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complex cdat(16*12),crot(16*12)
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real pp(32),softbits(9)
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np=2**ns-1
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softbits=0.0
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crot=cdat*cmplx(cos(phase),-sin(phase))
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softbits(1)=sum(imag(crot(1:32)*pp))
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softbits(2)=sum(real(crot(17:48)*pp))
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softbits(3)=sum(imag(crot(33:64)*pp))
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softbits(4)=sum(imag(crot(65:96)*pp))
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softbits(5)=sum(real(crot(81:112)*pp))
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softbits(6)=sum(imag(crot(97:128)*pp))
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softbits(7)=sum(imag(crot(129:160)*pp))
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softbits(8)=sum(real(crot(145:176)*pp))
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softbits(9)=sum(imag(crot(161:192)*pp))
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softbits=softbits/64.
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end subroutine mskcohdet
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subroutine downsample(ci,f0,co)
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parameter(NI=412*288,NO=NI/18)
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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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df=400.0/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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co=0.0
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co(0)=ct(i0)
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! b=3.0 !optimized for sequence detection
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b=6.0
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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(i0+i)*filt
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co(NO-i)=ct(i0-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
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subroutine getfc1(c,fs,fa,fb,fc1,xsnr)
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! include 'wsprlf_params.f90'
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parameter (NZ=288*412)
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parameter (NSPS=288)
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parameter (N2=2*NSPS)
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parameter (NFFT1=16*NSPS)
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parameter (NH1=NFFT1/2)
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complex c(0:NZ-1) !Complex waveform
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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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nspec=NZ/N2
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df1=fs/NFFT1
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s=0.
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do k=1,nspec
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ia=(k-1)*N2
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ib=ia+N2-1
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c2(0:N2-1)=c(ia:ib)
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c2(N2:)=0.
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call four2a(c2,NFFT1,1,-1,1)
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do i=0,NFFT1-1
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j=i
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if(j.gt.NH1) j=j-NFFT1
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s(j)=s(j) + real(c2(i))**2 + aimag(c2(i))**2
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enddo
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enddo
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! call smo121(s,NFFT1)
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smax=0.
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ipk=0
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fc1=0.
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ia=nint(fa/df1)
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|
ib=nint(fb/df1)
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do i=ia,ib
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f=i*df1
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if(s(i).gt.smax) then
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|
smax=s(i)
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|
ipk=i
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|
fc1=f
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endif
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! write(51,3001) f,s(i),db(s(i))
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! 3001 format(f10.3,e12.3,f10.3)
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|
enddo
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|
|
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! The following is for testing SNR calibration:
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sp3n=(s(ipk-1)+s(ipk)+s(ipk+1)) !Sig + 3*noise
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base=(sum(s)-sp3n)/(NFFT1-3.0) !Noise per bin
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psig=sp3n-3*base !Sig only
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pnoise=(2500.0/df1)*base !Noise in 2500 Hz
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xsnr=db(psig/pnoise)
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xsnr=xsnr+5.0
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return
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end subroutine getfc1
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|
|
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subroutine getfc2(c,npeaks,fs,fc1,fpks)
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|
|
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! include 'wsprlf_params.f90'
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|
parameter (NZ=288*412)
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|
parameter (NSPS=288)
|
|
parameter (N2=2*NSPS)
|
|
parameter (NFFT1=16*NSPS)
|
|
parameter (NH1=NFFT1/2)
|
|
|
|
complex c(0:NZ-1) !Complex waveform
|
|
complex cs(0:NZ-1) !For computing spectrum
|
|
real a(5)
|
|
real freqs(413),sp2(413),fpks(npeaks)
|
|
integer pkloc(1)
|
|
|
|
df=fs/NZ
|
|
baud=fs/NSPS
|
|
a(1)=-fc1
|
|
a(2:5)=0.
|
|
call twkfreq1(c,NZ,fs,a,cs) !Mix down by fc1
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|
|
|
! Filter, square, then FFT to get refined carrier frequency fc2.
|
|
call four2a(cs,NZ,1,-1,1) !To freq domain
|
|
|
|
ia=nint(0.75*baud/df)
|
|
cs(ia:NZ-1-ia)=0. !Save only freqs around fc1
|
|
! do i=1,NZ/2
|
|
! filt=1/(1+((i*df)**2/(0.50*baud)**2)**8)
|
|
! cs(i)=cs(i)*filt
|
|
! cs(NZ+1-i)=cs(NZ+1-i)*filt
|
|
! enddo
|
|
call four2a(cs,NZ,1,1,1) !Back to time domain
|
|
cs=cs/NZ
|
|
cs=cs*cs !Square the data
|
|
call four2a(cs,NZ,1,-1,1) !Compute squared spectrum
|
|
! Find two peaks separated by baud
|
|
pmax=0.
|
|
fc2=0.
|
|
! ja=nint(0.3*baud/df)
|
|
ja=nint(0.5*baud/df)
|
|
k=1
|
|
sp2=0.0
|
|
do j=-ja,ja
|
|
f2=j*df
|
|
ia=nint((f2-0.5*baud)/df)
|
|
if(ia.lt.0) ia=ia+NZ
|
|
ib=nint((f2+0.5*baud)/df)
|
|
p=real(cs(ia))**2 + aimag(cs(ia))**2 + &
|
|
real(cs(ib))**2 + aimag(cs(ib))**2
|
|
if(p.gt.pmax) then
|
|
pmax=p
|
|
fc2=0.5*f2
|
|
endif
|
|
freqs(k)=0.5*f2
|
|
sp2(k)=p
|
|
k=k+1
|
|
! write(52,1200) f2,p,db(p)
|
|
!1200 format(f10.3,2f15.3)
|
|
enddo
|
|
|
|
do i=1,npeaks
|
|
pkloc=maxloc(sp2)
|
|
ipk=pkloc(1)
|
|
fpks(i)=freqs(ipk)
|
|
ipk0=max(1,ipk-2)
|
|
ipk1=min(413,ipk+2)
|
|
! ipk0=ipk
|
|
! ipk1=ipk
|
|
sp2(ipk0:ipk1)=0.0
|
|
enddo
|
|
return
|
|
end subroutine getfc2
|