551 lines
15 KiB
Plaintext
551 lines
15 KiB
Plaintext
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program wsprcpmd
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! Decode WSPRCPM data read from *.c2 or *.wav files.
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! WSPRCPM is a WSPR-like mode based on full-response CPM.
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!
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! Currently configured to use (204,68) r=1/3 LDPC code, regular column weight 3.
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! 50 data bits + 14 bit CRC + 4 "0" bits. The 4 "0" bits are unused bits that
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! are not transmitted. At the decoder, these bits are treated as "AP" bits.
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! This shortens the code to (200,64) r=0.32, slightly decreasing the code rate.
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!
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! Frame format is:
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! d100 p32 d100 (232) channel symbols
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!
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use crc
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include 'wsprcpm_params.f90'
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parameter(NMAX=120*12000)
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character arg*8,message*22,cbits*50,infile*80,fname*16,datetime*11
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character*22 decodes(100)
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character*120 data_dir
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character*32 uwbits
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character*68 dmsg
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complex c2(0:120*12000/32-1) !Complex waveform
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complex cframe(0:216*200-1) !Complex waveform
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complex cd(0:216*10-1) !Complex waveform
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complex c1(0:9,0:1),c0(0:9,0:1)
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complex ccor(0:1,216)
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complex csum,cterm
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real*8 fMHz
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real rxdata(ND),llr(204) !Soft symbols
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real sbits(216),sbits1(216),sbits3(216)
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real ps(0:8191),psbest(0:8191)
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real candidates(100,2)
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integer iuniqueword0
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integer isync(200) !Unique word
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integer isync2(216)
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integer ipreamble(16) !Preamble vector
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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,target :: idat(9)
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integer*1 decoded(68),apmask(204),cw(204)
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integer*1 hbits(216),hbits1(216),hbits3(216)
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data ipreamble/1,1,1,1,0,0,0,0,0,0,0,0,1,1,1,1/
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data iuniqueword0/z'30C9E8AD'/
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write(uwbits,'(b32.32)') iuniqueword0
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read(uwbits,'(32i1)') isync(1:32)
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read(uwbits,'(32i1)') isync(33:64)
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read(uwbits,'(32i1)') isync(65:96)
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read(uwbits,'(32i1)') isync(97:128)
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read(uwbits,'(32i1)') isync(129:160)
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read(uwbits,'(32i1)') isync(161:192)
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read(uwbits,'(8i1)') isync(193:200)
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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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baud=1.0/tt !Keying rate for "itone" symbols (baud)
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txt=NZ*dt !Transmission length (s)
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h=1.00 !h=0.8 seems to be optimum for AWGN sensitivity (not for fading)
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twopi=8.0*atan(1.0)
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isync2(1:100)=isync(1:100)
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isync2(101:104)=0 ! This is *not* backwards.
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isync2(105:112)=1
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isync2(113:116)=0
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isync2(117:216)=isync(101:200)
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! data sync tone
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! 0 0 0
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! 0 1 1
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! 1 0 2
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! 1 1 3
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dphi=twopi*baud*(h/2.0)*dt*20 ! dt*10 is samp interval after downsample
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do j=0,1
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if(j.eq.0) then
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dphi0=-3*dphi
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dphi1=+1*dphi
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else
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dphi0=-1*dphi
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dphi1=+3*dphi
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endif
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phi0=0.0
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phi1=0.0
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do i=0,9
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c1(i,j)=cmplx(cos(phi1),sin(phi1))
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c0(i,j)=cmplx(cos(phi0),sin(phi0))
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phi1=mod(phi1+dphi1,twopi)
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phi0=mod(phi0+dphi0,twopi)
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enddo
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enddo
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nargs=iargc()
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if(nargs.lt.1) then
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print*,'Usage: wsprcpmd [-a <data_dir>] [-f fMHz] [-c ncoh] 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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ncoh=1
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npdi=16
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if(arg(1:2).eq.'-c') then
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call getarg(iarg+1,arg)
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read(arg,*) ncoh
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iarg=iarg+2
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npdi=16/ncoh
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endif
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! write(*,*) 'ncoh: ',ncoh,' npdi: ',npdi
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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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xs1=0.0
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xs2=0.0
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fr1=0.0
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fr2=0.0
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nav=0
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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 wsprcpm_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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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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nsync=16
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call getcandidate2(c2,npts,fs,fa,fb,ncand,candidates) !First approx for freq
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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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xmax=-1e32
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do i=-5,5
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ft=fc0+i*0.2
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call noncoherent_frame_sync(c2,ft,isync2,is,xf1)
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if(xf1.gt.xmax) then
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xmax=xf1
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fc1=ft
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is0=is
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endif
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enddo
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call coherent_preamble_fsync(c2,ipreamble,nsync,NSPS,is0,fc1,fcest,xp1)
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call noncoherent_frame_sync(c2,fcest,isync2,istart,xf2)
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write(*,'(i5,i5,i5,4(f11.5,2x))') ifile,iii,istart,fc0,fc1,fcest
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do ijitter=0,4
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io=-10*(ijitter/2+1)
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if(mod(ijitter,2).eq.0) io=10*(ijitter/2)
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ib=max(0,istart+io)
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cframe=c2(ib:ib+216*200-1)
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call downsample2(cframe,fcest,cd)
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s2=sum(cd*conjg(cd))/(10*216)
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cd=cd/sqrt(s2)
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do nseq=1,7
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if( nseq.eq.1 ) then ! noncoherent single-symbol detection
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sbits1=0.0
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do ibit=1,216
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j=isync2(ibit)
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ib=(ibit-1)*10
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ccor(1,ibit)=sum(cd(ib:ib+9)*conjg(c1(0:9,j)))
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ccor(0,ibit)=sum(cd(ib:ib+9)*conjg(c0(0:9,j)))
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sbits1(ibit)=abs(ccor(1,ibit))-abs(ccor(0,ibit))
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hbits1(ibit)=0
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if(sbits1(ibit).gt.0) hbits1(ibit)=1
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enddo
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sbits=sbits1
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hbits=hbits1
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sbits3=sbits1
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hbits3=hbits1
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elseif( nseq.ge.2 ) then
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ps=0
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if( nseq.eq. 2 ) nbit=3
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if( nseq.eq. 3 ) nbit=5
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if( nseq.eq. 4 ) nbit=7
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if( nseq.eq. 5 ) nbit=9
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if( nseq.eq. 6 ) nbit=11
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if( nseq.eq. 7 ) nbit=13
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numseq=2**(nbit)
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do ibit=nbit/2+1,216-nbit/2
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ps=0.0
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pmax=0.0
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do iseq=0,numseq-1
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csum=0.0
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cterm=1.0
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k=1
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do i=nbit-1,0,-1
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ibb=iand(iseq/(2**i),1)
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csum=csum+ccor(ibb,ibit-(nbit/2+1)+k)*cterm
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cterm=-cterm
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k=k+1
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enddo
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ps(iseq)=abs(csum)
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if( ps(iseq) .gt. pmax ) then
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pmax=ps(iseq)
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ibflag=1
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endif
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enddo
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if( ibflag .eq. 1 ) then
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psbest=ps
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ibflag=0
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endif
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call getmetric2(2**(nbit/2),psbest,numseq,sbits3(ibit))
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hbits3(ibit)=0
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if(sbits3(ibit).gt.0) hbits3(ibit)=1
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enddo
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sbits=sbits3
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hbits=hbits3
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endif
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rxdata(1:100)=sbits(1:100)
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rxdata(101:200)=sbits(117:216);
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rxav=sum(rxdata(1:200))/200.0
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rx2av=sum(rxdata(1:200)*rxdata(1:200))/200.0
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rxsig=sqrt(rx2av-rxav*rxav)
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rxdata=rxdata/rxsig
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sigma=0.90
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llr(201:204)=-5.0
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llr(1:200)=2*rxdata/(sigma*sigma)
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apmask=0
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apmask(201:204)=1
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max_iterations=40
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ifer=0
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call bpdecode204(llr,apmask,max_iterations,decoded,cw,nharderror,niterations)
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nhardmin=-1
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if(nharderror.lt.0) call osd204(llr,apmask,5,decoded,cw,nhardmin,dmin)
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if(sum(decoded).eq.0) cycle
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if(nhardmin.ge.0 .or. nharderror.ge.0) then
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idat=0
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write(dmsg,'(68i1)') decoded
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read(dmsg(1:50),'(6b8.8,b2.2)') idat(1:7)
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idat(7)=idat(7)*64
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read(dmsg(51:64),'(b14.14)') ndec_crc
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ncalc_crc=iand(crc14(c_loc(idat),9),z'FFFF')
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nbadcrc=1
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if(ncalc_crc .eq. ndec_crc) nbadcrc=0
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else
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cycle
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endif
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if( nbadcrc.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(8b8,b4)
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idat(7)=ishft(idat(7),6)
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call wqdecode(idat,message,itype)
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idupe=0
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do i=1,ndecodes
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if(decodes(i).eq.message) idupe=1
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enddo
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if(idupe.eq.1) goto 888
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ndecodes=ndecodes+1
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decodes(ndecodes)=message
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nsnr=nint(xsnr)
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freq=fMHz + 1.d-6*(fc1+fbest)
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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,ijitter,nharderror,nhardmin
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1212 format(a4,i4,f5.1,f11.6,i3,2x,a22,a1,i5,i5,i5,i5,i5)
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goto 888
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endif
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enddo ! nseq
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enddo !jitter
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888 continue
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enddo !candidate list
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enddo !files
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write(*,1120)
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1120 format("<DecodeFinished>")
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999 end program wsprcpmd
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subroutine coherent_preamble_fsync(c2,ipreamble,nsync,nsps,istart,fc0,fc1,xmax)
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complex c2(0:120*12000/32-1)
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complex cpreamble(0:16*200-1)
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complex ctmp1(0:4*16*200-1)
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complex ctwkp(0:16*200-1)
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complex ccohp(0:15)
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integer ipreamble(nsync)
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logical first/.true./
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save dt,first,h,twopi,cpreamble
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if(first) then
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baud=12000.0/6400.0
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dt=32.0/12000.0
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h=1.00
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twopi=8.0*atan(1.0)
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k=0
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phi=0.0
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dphi=twopi*baud*0.5*h*dt
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do i=1,16
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dp=dphi
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if(ipreamble(i).eq.0) dp=-dphi
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do j=1,200
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cpreamble(k)=cmplx(cos(phi),sin(phi))
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phi=mod(phi+dp,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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endif
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dphi=twopi*fc0*dt
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ctwkp=cmplx(0.0,0.0)
|
||
|
|
phi=0
|
||
|
|
do i=0,nsync*nsps-1
|
||
|
|
ctwkp(i)=cpreamble(i)*cmplx(cos(phi),sin(phi))
|
||
|
|
phi=mod(phi+dphi,twopi)
|
||
|
|
enddo
|
||
|
|
ipstart=istart+100*200
|
||
|
|
ctmp1=0.0
|
||
|
|
ctmp1(0:16*200-1)=c2(ipstart:ipstart+16*200-1)*conjg(ctwkp)
|
||
|
|
call four2a(ctmp1,4*16*200,1,-1,1) !c2c FFT to freq domain
|
||
|
|
xmax=0.0
|
||
|
|
ctmp1=cshift(ctmp1,-200)
|
||
|
|
dfp=1/(4*6400.0/12000.0*16)
|
||
|
|
do i=150,250
|
||
|
|
xa=abs(ctmp1(i))
|
||
|
|
if(xa.gt.xmax) then
|
||
|
|
ishift=i
|
||
|
|
xmax=xa
|
||
|
|
endif
|
||
|
|
enddo
|
||
|
|
delta=(ishift-200)*dfp
|
||
|
|
xm1=abs(ctmp1(ishift-1))
|
||
|
|
x0=abs(ctmp1(ishift))
|
||
|
|
xp1=abs(ctmp1(ishift+1))
|
||
|
|
xint=(log(xm1)-log(xp1))/(log(xm1)+log(xp1)-2*log(x0))
|
||
|
|
delta2=delta+xint*dfp/2.0
|
||
|
|
fc1=fc0+delta2
|
||
|
|
return
|
||
|
|
end subroutine coherent_preamble_fsync
|
||
|
|
|
||
|
|
|
||
|
|
subroutine noncoherent_frame_sync(c2,fc,isync2,istart,ssmax)
|
||
|
|
complex c2(0:120*12000/32-1)
|
||
|
|
complex ct0(0:199),ct1(0:199),ct2(0:199),ct3(0:199)
|
||
|
|
integer isync2(216)
|
||
|
|
|
||
|
|
twopi=8.0*atan(1.0)
|
||
|
|
h=1.0
|
||
|
|
dt=32.0/12000.0
|
||
|
|
baud=12000.0/6400.0
|
||
|
|
imax=370 ! defines dt search range (375 samples/s)
|
||
|
|
ssmax=-1e32
|
||
|
|
izero=375
|
||
|
|
do it = -imax,imax,10
|
||
|
|
! noncoherent wspr-type dt estimation
|
||
|
|
dp0=twopi*(fc-1.5*h*baud)*dt
|
||
|
|
dp1=twopi*(fc-0.5*h*baud)*dt
|
||
|
|
dp2=twopi*(fc+0.5*h*baud)*dt
|
||
|
|
dp3=twopi*(fc+1.5*h*baud)*dt
|
||
|
|
th0=0.0
|
||
|
|
th1=0.0
|
||
|
|
th2=0.0
|
||
|
|
th3=0.0
|
||
|
|
do i=0,199
|
||
|
|
ct0(i)=cmplx(cos(th0),sin(th0))
|
||
|
|
ct1(i)=cmplx(cos(th1),sin(th1))
|
||
|
|
ct2(i)=cmplx(cos(th2),sin(th2))
|
||
|
|
ct3(i)=cmplx(cos(th3),sin(th3))
|
||
|
|
th0=mod(th0+dp0,twopi)
|
||
|
|
th1=mod(th1+dp1,twopi)
|
||
|
|
th2=mod(th2+dp2,twopi)
|
||
|
|
th3=mod(th3+dp3,twopi)
|
||
|
|
enddo
|
||
|
|
ss=0.0
|
||
|
|
totp=0.0
|
||
|
|
do is=1,216
|
||
|
|
i0=izero+it+(is-1)*200
|
||
|
|
p0=abs(sum(c2(i0:i0+199)*conjg(ct0)))
|
||
|
|
p1=abs(sum(c2(i0:i0+199)*conjg(ct1)))
|
||
|
|
p2=abs(sum(c2(i0:i0+199)*conjg(ct2)))
|
||
|
|
p3=abs(sum(c2(i0:i0+199)*conjg(ct3)))
|
||
|
|
p0=sqrt(p0)
|
||
|
|
p1=sqrt(p1)
|
||
|
|
p2=sqrt(p2)
|
||
|
|
p3=sqrt(p3)
|
||
|
|
|
||
|
|
totp=totp+p0+p1+p2+p3
|
||
|
|
! cmet=(p1+p3)-(p0+p2)
|
||
|
|
cmet=max(p1,p3)-max(p0,p2) ! This works better near threshold SNR
|
||
|
|
if(isync2(is).eq.0) ss=ss-cmet
|
||
|
|
if(isync2(is).eq.1) ss=ss+cmet
|
||
|
|
enddo
|
||
|
|
ss=ss/totp
|
||
|
|
if(ss.gt.ssmax) then
|
||
|
|
ioffset=it
|
||
|
|
ssmax=ss
|
||
|
|
endif
|
||
|
|
enddo
|
||
|
|
istart=izero+ioffset
|
||
|
|
return
|
||
|
|
end subroutine noncoherent_frame_sync
|
||
|
|
|
||
|
|
subroutine getmetric2(ib,ps,ns,xmet)
|
||
|
|
real ps(0:ns-1)
|
||
|
|
xm1=0
|
||
|
|
xm0=0
|
||
|
|
do i=0,ns-1
|
||
|
|
if( iand(i/ib,1) .eq. 1 .and. ps(i) .gt. xm1 ) xm1=ps(i)
|
||
|
|
if( iand(i/ib,1) .eq. 0 .and. ps(i) .gt. xm0 ) xm0=ps(i)
|
||
|
|
enddo
|
||
|
|
xmet=xm1-xm0
|
||
|
|
return
|
||
|
|
end subroutine getmetric2
|
||
|
|
|
||
|
|
subroutine downsample2(ci,f0,co)
|
||
|
|
parameter(NI=216*200,NH=NI/2,NO=NI/20) ! downsample from 200 samples per symbol to 10
|
||
|
|
complex ci(0:NI-1),ct(0:NI-1)
|
||
|
|
complex co(0:NO-1)
|
||
|
|
fs=12000.0/32.0
|
||
|
|
df=fs/NI
|
||
|
|
ct=ci
|
||
|
|
call four2a(ct,NI,1,-1,1) !c2c FFT to freq domain
|
||
|
|
i0=nint(f0/df)
|
||
|
|
ct=cshift(ct,i0)
|
||
|
|
co=0.0
|
||
|
|
co(0)=ct(0)
|
||
|
|
b=8.0
|
||
|
|
do i=1,NO/2
|
||
|
|
arg=(i*df/b)**2
|
||
|
|
filt=exp(-arg)
|
||
|
|
co(i)=ct(i)*filt
|
||
|
|
co(NO-i)=ct(NI-i)*filt
|
||
|
|
enddo
|
||
|
|
co=co/NO
|
||
|
|
call four2a(co,NO,1,1,1) !c2c FFT back to time domain
|
||
|
|
return
|
||
|
|
end subroutine downsample2
|
||
|
|
|
||
|
|
subroutine getcandidate2(c,npts,fs,fa,fb,ncand,candidates)
|
||
|
|
parameter(NDAT=200,NFFT1=120*12000/32,NH1=NFFT1/2,NFFT2=120*12000/320,NH2=NFFT2/2)
|
||
|
|
complex c(0:npts-1) !Complex waveform
|
||
|
|
complex cc(0:NFFT1-1)
|
||
|
|
complex csfil(0:NFFT2-1)
|
||
|
|
complex cwork(0:NFFT2-1)
|
||
|
|
real bigspec(0:NFFT2-1)
|
||
|
|
complex c2(0:NFFT1-1) !Short spectra
|
||
|
|
real s(-NH1+1:NH1) !Coarse spectrum
|
||
|
|
real ss(-NH1+1:NH1) !Smoothed coarse spectrum
|
||
|
|
real candidates(100,2)
|
||
|
|
integer indx(NFFT2-1)
|
||
|
|
logical first
|
||
|
|
data first/.true./
|
||
|
|
save first,w,df,csfil
|
||
|
|
|
||
|
|
if(first) then
|
||
|
|
df=10*fs/NFFT1
|
||
|
|
csfil=cmplx(0.0,0.0)
|
||
|
|
do i=0,NFFT2-1
|
||
|
|
csfil(i)=exp(-((i-NH2)/20.0)**2)
|
||
|
|
enddo
|
||
|
|
csfil=cshift(csfil,NH2)
|
||
|
|
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))-30.0
|
||
|
|
endif
|
||
|
|
enddo
|
||
|
|
! do i=1,ncand
|
||
|
|
! write(*,*) i,candidates(i,1),candidates(i,2)
|
||
|
|
! enddo
|
||
|
|
return
|
||
|
|
end subroutine getcandidate2
|
||
|
|
|
||
|
|
subroutine wsprcpm_downsample(iwave,c)
|
||
|
|
|
||
|
|
! Input: i*2 data in iwave() at sample rate 12000 Hz
|
||
|
|
! Output: Complex data in c(), sampled at 400 Hz
|
||
|
|
|
||
|
|
include 'wsprcpm_params.f90'
|
||
|
|
parameter (NMAX=120*12000,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 wsprcpm_downsample
|
||
|
|
|