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https://github.com/saitohirga/WSJT-X.git
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5984d5ea42
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7195 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
426 lines
13 KiB
Fortran
426 lines
13 KiB
Fortran
subroutine detectmsk40(cbig,n,mycall,hiscall,lines,nmessages, &
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nutc,ntol,t00)
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use timer_module, only: timer
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parameter (NSPM=240, NPTS=3*NSPM, MAXSTEPS=7500, NFFT=3*NSPM, MAXCAND=15)
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character*4 rpt(0:15)
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character*6 mycall,hiscall,mycall0,hiscall0
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character*22 hashmsg,msgreceived
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character*80 lines(100)
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complex cbig(n)
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complex cdat(NPTS) !Analytic signal
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complex cdat2(NPTS)
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complex c(NSPM)
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complex ctmp(NFFT)
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complex cb(42) !Complex waveform for sync word
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complex cbr(42) !Complex waveform for reversed sync word
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complex cfac,cca,ccb
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complex ccr(NPTS)
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complex ccr1(NPTS)
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complex ccr2(NPTS)
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complex bb(6)
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integer s8(8),s8r(8),hardbits(40)
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integer, dimension(1) :: iloc
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! integer nhashes(0:15)
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integer indices(MAXSTEPS)
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integer ipeaks(10)
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integer*1 cw(32)
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integer*1 decoded(16)
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integer*1 testcw(32)
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logical ismask(NFFT)
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real cbi(42),cbq(42)
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real detmet(-2:MAXSTEPS+3)
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real detmet2(-2:MAXSTEPS+3)
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real detfer(MAXSTEPS)
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real rcw(12)
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real ddr(NPTS)
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real ferrs(MAXCAND)
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real llr(32)
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real pp(12) !Half-sine pulse shape
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real snrs(MAXCAND)
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real softbits(40)
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real times(MAXCAND)
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real tonespec(NFFT)
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real*8 dt, df, fs, pi, twopi
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real*8 lratio(32)
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logical first
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data first/.true./
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data mycall0/'dummy'/,hiscall0/'dummy'/
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data rpt/"-03 ","+00 ","+03 ","+06 ","+10 ","+13 ","+16 ", &
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"R-03","R+00","R+03","R+06","R+10","R+13","R+16", &
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"RRR ","73 "/
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data s8/0,1,1,1,0,0,1,0/
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data s8r/1,0,1,1,0,0,0,1/
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! codeword for the message <K9AN K1JT> RRR
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data testcw/0,1,0,0,0,1,0,1,0,0,1,1,1,1,0,1,0,1,1,1,1,1,0,0,0,0,0,0,1,1,1,0/
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save df,first,cb,cbr,fs,pi,twopi,dt,s8,s8r,rcw,pp,nmatchedfilter,rpt,mycall0,hiscall0
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if(first) then
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nmatchedfilter=1
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! define half-sine pulse and raised-cosine edge window
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pi=4d0*datan(1d0)
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twopi=8d0*datan(1d0)
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fs=12000.0
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dt=1.0/fs
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df=fs/NFFT
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do i=1,12
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angle=(i-1)*pi/12.0
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pp(i)=sin(angle)
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rcw(i)=(1-cos(angle))/2
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enddo
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! define the sync word waveforms
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s8=2*s8-1
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cbq(1:6)=pp(7:12)*s8(1)
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cbq(7:18)=pp*s8(3)
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cbq(19:30)=pp*s8(5)
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cbq(31:42)=pp*s8(7)
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cbi(1:12)=pp*s8(2)
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cbi(13:24)=pp*s8(4)
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cbi(25:36)=pp*s8(6)
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cbi(37:42)=pp(1:6)*s8(8)
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cb=cmplx(cbi,cbq)
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s8r=2*s8r-1
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cbq(1:6)=pp(7:12)*s8r(1)
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cbq(7:18)=pp*s8r(3)
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cbq(19:30)=pp*s8r(5)
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cbq(31:42)=pp*s8r(7)
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cbi(1:12)=pp*s8r(2)
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cbi(13:24)=pp*s8r(4)
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cbi(25:36)=pp*s8r(6)
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cbi(37:42)=pp(1:6)*s8r(8)
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cbr=cmplx(cbi,cbq)
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first=.false.
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endif
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if(mycall.ne.mycall0 .or. hiscall.ne.hiscall0) then
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! do i=0,15
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! hashmsg=trim(mycall)//' '//trim(hiscall)//' '//rpt(i)
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hashmsg=trim(mycall)//' '//trim(hiscall)
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call fmtmsg(hashmsg,iz)
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call hash(hashmsg,22,ihash)
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! nhashes(i)=iand(ihash,4095)
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ihash=iand(ihash,4095)
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! enddo
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mycall0=mycall
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hiscall0=hiscall
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endif
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! Fill the detmet, detferr arrays
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nstepsize=60 ! 5ms steps
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nstep=(n-NPTS)/nstepsize
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detmet=0
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detmet2=0
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detfer=-999.99
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do istp=1,nstep
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ns=1+nstepsize*(istp-1)
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ne=ns+NPTS-1
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if( ne .gt. n ) exit
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ctmp=cmplx(0.0,0.0)
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ctmp(1:NPTS)=cbig(ns:ne)
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! Coarse carrier frequency sync - seek tones at 2000 Hz and 4000 Hz in
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! squared signal spectrum.
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! search range for coarse frequency error is +/- 100 Hz
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ctmp=ctmp**2
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ctmp(1:12)=ctmp(1:12)*rcw
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ctmp(NPTS-11:NPTS)=ctmp(NPTS-11:NPTS)*rcw(12:1:-1)
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call four2a(ctmp,NFFT,1,-1,1)
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tonespec=abs(ctmp)**2
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ihlo=(4000-2*ntol)/df+1
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ihhi=(4000+2*ntol)/df+1
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ismask=.false.
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ismask(ihlo:ihhi)=.true. ! high tone search window
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iloc=maxloc(tonespec,ismask)
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ihpk=iloc(1)
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deltah=-real( (ctmp(ihpk-1)-ctmp(ihpk+1)) / (2*ctmp(ihpk)-ctmp(ihpk-1)-ctmp(ihpk+1)) )
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ah=tonespec(ihpk)
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ahavp=(sum(tonespec,ismask)-ah)/count(ismask)
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trath=ah/(ahavp+0.01)
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illo=(2000-2*ntol)/df+1
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ilhi=(2000+2*ntol)/df+1
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ismask=.false.
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ismask(illo:ilhi)=.true. ! window for low tone
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iloc=maxloc(tonespec,ismask)
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ilpk=iloc(1)
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deltal=-real( (ctmp(ilpk-1)-ctmp(ilpk+1)) / (2*ctmp(ilpk)-ctmp(ilpk-1)-ctmp(ilpk+1)) )
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al=tonespec(ilpk)
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alavp=(sum(tonespec,ismask)-al)/count(ismask)
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tratl=al/(alavp+0.01)
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fdiff=(ihpk+deltah-ilpk-deltal)*df
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i2000=nint(2000/df)+1
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i4000=nint(4000/df)+1
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ferrh=(ihpk+deltah-i4000)*df/2.0
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ferrl=(ilpk+deltal-i2000)*df/2.0
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if( ah .ge. al ) then
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ferr=ferrh
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else
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ferr=ferrl
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endif
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detmet(istp)=max(ah,al)
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detmet2(istp)=max(trath,tratl)
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detfer(istp)=ferr
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! write(*,*) istp,ilpk,ihpk,ah,al
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enddo ! end of detection-metric and frequency error estimation loop
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call indexx(detmet(1:nstep),nstep,indices) !find median of detection metric vector
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xmed=detmet(indices(nstep/4))
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detmet=detmet/xmed ! noise floor of detection metric is 1.0
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ndet=0
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!do i=1,nstep
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!write(77,*) i,detmet(i),detmet2(i),detfer(i)
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!enddo
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do ip=1,MAXCAND ! find candidates
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iloc=maxloc(detmet(1:nstep))
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il=iloc(1)
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if( (detmet(il) .lt. 4.2) ) exit
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if( abs(detfer(il)) .le. ntol ) then
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ndet=ndet+1
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times(ndet)=((il-1)*nstepsize+NPTS/2)*dt
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ferrs(ndet)=detfer(il)
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snrs(ndet)=12.0*log10(detmet(il)-1)/2-8.0
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endif
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detmet(max(1,il-3):min(nstep,il+3))=0.0
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! detmet(il)=0.0
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enddo
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if( ndet .lt. 3 ) then
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do ip=1,MAXCAND-ndet ! Find candidates
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iloc=maxloc(detmet2(1:nstep))
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il=iloc(1)
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if( (detmet2(il) .lt. 20.0) ) exit
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if( abs(detfer(il)) .le. ntol ) then
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ndet=ndet+1
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times(ndet)=((il-1)*nstepsize+NSPM/2)*dt
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ferrs(ndet)=detfer(il)
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snrs(ndet)=12.0*log10(detmet2(il))/2-9.0
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endif
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detmet2(max(1,il-1):min(nstep,il+1))=0.0
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! detmet2(il)=0.0
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enddo
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endif
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! do ip=1,ndet
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! write(*,'(i5,f7.2,f7.2,f7.2)') ip,times(ip),snrs(ip),ferrs(ip)
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! enddo
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nmessages=0
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lines=char(0)
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ncalls=0
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do ip=1,ndet !run through the candidates and try to sync/demod/decode
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imid=times(ip)*fs
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if( imid .lt. NPTS/2 ) imid=NPTS/2
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if( imid .gt. n-NPTS/2 ) imid=n-NPTS/2
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t0=times(ip) + t00
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cdat=cbig(imid-NPTS/2+1:imid+NPTS/2)
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ferr=ferrs(ip)
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xsnr=snrs(ip)
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nsnr=nint(snrs(ip))
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if( nsnr .lt. -5 ) nsnr=-5
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if( nsnr .gt. 25 ) nsnr=25
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! remove coarse freq error
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call tweak1(cdat,NPTS,-(1500+ferr),cdat)
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! attempt frame synchronization
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! correlate with sync word waveforms
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ccr=0
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ccr1=0
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ccr2=0
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do i=1,NPTS-(40*6+41)
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ccr1(i)=sum(cdat(i:i+41)*conjg(cbr))
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ccr2(i)=sum(cdat(i+40*6:i+40*6+41)*conjg(cbr))
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enddo
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ccr=ccr1+ccr2
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ddr=abs(ccr1)*abs(ccr2)
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crmax=maxval(abs(ccr))
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!do i=1,NPTS
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!write(15,*) i,abs(ccr(i)),ddr(i),abs(cdat(i))
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!enddo
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! Find 6 largest peaks
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do ipk=1,6
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iloc=maxloc(ddr)
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ic1=iloc(1)
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ipeaks(ipk)=ic1
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ddr(max(1,ic1-7):min(NPTS-40*6-41,ic1+7))=0.0
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enddo
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!do i=1,6
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!write(*,*) i,ipeaks(i)
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!enddo
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do ipk=1,4
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! we want ic to be the index of the first sample of the frame
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ic0=ipeaks(ipk)
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! fine adjustment of sync index
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do i=1,6
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if( ic0+11+NSPM .le. NPTS ) then
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bb(i) = sum( ( cdat(ic0+i-1+6:ic0+i-1+6+NSPM:6) * conjg( cdat(ic0+i-1:ic0+i-1+NSPM:6) ) )**2 )
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else
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bb(i) = sum( ( cdat(ic0+i-1+6:NPTS:6) * conjg( cdat(ic0+i-1:NPTS-6:6) ) )**2 )
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endif
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enddo
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iloc=maxloc(abs(bb))
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ibb=iloc(1)
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bba=abs(bb(ibb))
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bbp=atan2(-imag(bb(ibb)),-real(bb(ibb)))/(2*twopi*6*dt)
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!write(*,*) abs(bb),bbp
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if( ibb .le. 3 ) ibb=ibb-1
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if( ibb .gt. 3 ) ibb=ibb-7
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do id=1,3 ! slicer dither.
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if( id .eq. 1 ) is=0
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if( id .eq. 2 ) is=-1
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if( id .eq. 3 ) is=1
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! Adjust frame index to place peak of bb at desired lag
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ic=ic0+ibb+is
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if( ic .lt. 1 ) ic=ic+NSPM
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! Estimate fine frequency error.
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cca=sum(cdat(ic:ic+41)*conjg(cbr))
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if( ic+40*6+41 .le. NPTS ) then
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ccb=sum(cdat(ic+40*6:ic+40*6+41)*conjg(cbr))
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cfac=ccb*conjg(cca)
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ferr2=atan2(imag(cfac),real(cfac))/(twopi*40*6*dt)
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else
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ccb=sum(cdat(ic-40*6:ic-40*6+41)*conjg(cbr))
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cfac=cca*conjg(ccb)
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ferr2=atan2(imag(cfac),real(cfac))/(twopi*40*6*dt)
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endif
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do idf=0,2 ! frequency jitter
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if( idf .eq. 0 ) then
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deltaf=0.0
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elseif( mod(idf,2) .eq. 0 ) then
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deltaf=2.5*idf
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else
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deltaf=-2.5*(idf+1)
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endif
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! Remove fine frequency error
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call tweak1(cdat,NPTS,-(ferr2+deltaf),cdat2)
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! place the beginning of frame at index NSPM+1
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cdat2=cshift(cdat2,ic-(NSPM+1))
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do iav=1,4 ! Frame averaging patterns
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if( iav .eq. 1 ) then
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c=cdat2(NSPM+1:2*NSPM)
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elseif( iav .eq. 2 ) then
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c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM)
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elseif( iav .eq. 3 ) then
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c=cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:3*NSPM)
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elseif( iav .eq. 4 ) then
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c=cdat2(1:NSPM)+cdat2(NSPM+1:2*NSPM)+cdat2(2*NSPM+1:3*NSPM)
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endif
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! Estimate final frequency error and carrier phase.
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cca=sum(c(1:1+41)*conjg(cbr))
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phase0=atan2(imag(cca),real(cca))
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do ipha=1,3
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if( ipha.eq.2 ) phase0=phase0-30*pi/180.0
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if( ipha.eq.3 ) phase0=phase0+30*pi/180.0
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! Remove phase error - want constellation rotated so that sample points lie on I/Q axes
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cfac=cmplx(cos(phase0),sin(phase0))
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c=c*conjg(cfac)
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if( nmatchedfilter .eq. 0 ) then
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do i=1, 20
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softbits(2*i-1)=imag(c(1+(i-1)*12))
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softbits(2*i)=real(c(7+(i-1)*12))
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enddo
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else ! matched filter
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softbits(1)=sum(imag(c(1:6))*pp(7:12))+sum(imag(c(NSPM-5:NSPM))*pp(1:6))
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softbits(2)=sum(real(c(1:12))*pp)
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do i=2,20
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softbits(2*i-1)=sum(imag(c(1+(i-1)*12-6:1+(i-1)*12+5))*pp)
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softbits(2*i)=sum(real(c(7+(i-1)*12-6:7+(i-1)*12+5))*pp)
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enddo
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endif
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hardbits=0 ! use sync word hard error weight to decide whether to send to decoder
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do i=1, 40
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if( softbits(i) .ge. 0.0 ) then
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hardbits(i)=1
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endif
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enddo
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nbadsync1=(8-sum( (2*hardbits(1:8)-1)*s8r ) )/2
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nbadsync=nbadsync1
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if( nbadsync .gt. 3 ) cycle
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! nerr=0
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! do i=1,32
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! if( testcw(i) .ne. hardbits(i+8) ) nerr=nerr+1
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! enddo
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! normalize the softsymbols before submitting to decoder
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sav=sum(softbits)/40
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s2av=sum(softbits*softbits)/40
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ssig=sqrt(s2av-sav*sav)
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softbits=softbits/ssig
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sigma=0.75
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if(xsnr.lt.0.0) sigma=0.75-0.0875*xsnr
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lratio(1:32)=exp(2.0*softbits(9:40)/(sigma*sigma)) ! Use this for Radford Neal's routines
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llr(1:32)=2.0*softbits(9:40)/(sigma*sigma) ! Use log likelihood for bpdecode40
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max_iterations=5
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max_dither=1
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call bpdecode40(llr,max_iterations, decoded, niterations)
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ncalls=ncalls+1
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nhashflag=0
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if( niterations .ge. 0 ) then
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call encode_msk40(decoded,cw)
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! call ldpc_encode(decoded,cw)
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nhammd=0
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cord=0.0
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do i=1,32
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if( cw(i) .ne. hardbits(i+8) ) then
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nhammd=nhammd+1
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cord=cord+abs(softbits(i+8))
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endif
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enddo
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imsg=0
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do i=1,16
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imsg=ishft(imsg,1)+iand(1,decoded(17-i))
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enddo
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nrxrpt=iand(imsg,15)
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nrxhash=(imsg-nrxrpt)/16
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! if( nhammd .le. 5 .and. cord .lt. 1.7 .and. nrxhash .eq. nhashes(nrxrpt) ) then
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if( nhammd .le. 5 .and. cord .lt. 1.7 .and. nrxhash .eq. ihash ) then
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fest=1500+ferr+ferr2+deltaf
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!write(14,'(i6.6,11i6,f7.1,f7.1)') nutc,ip,ipk,id,idf,iav,ipha,niterations,nbadsync,nrxrpt,ncalls,nhammd,cord,xsnr
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nhashflag=1
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msgreceived=' '
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nmessages=1
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write(msgreceived,'(a1,a,1x,a,a1,1x,a4)') "<",trim(mycall), &
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trim(hiscall),">",rpt(nrxrpt)
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write(lines(nmessages),1020) nutc,nsnr,t0,nint(fest),msgreceived
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1020 format(i6.6,i4,f5.1,i5,' & ',a22)
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return
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endif
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endif
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enddo ! phase loop
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enddo ! frame averaging loop
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enddo ! frequency dithering loop
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enddo ! slicer dither loop
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enddo ! time-sync correlation-peak loop
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enddo ! candidate loop
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return
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end subroutine detectmsk40
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