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More work on msk40.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6968 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
This commit is contained in:
Steven Franke
parent
5aa3657fc6
commit
6e45134550
@ -192,9 +192,9 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc,ntol,t00)
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enddo
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cc=cc1+cc2
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dd=abs(cc1)*abs(cc2)
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do i=1,NPTS-(32*6+41)
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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+32*6:i+32*6+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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@ -202,7 +202,8 @@ subroutine detectmsk144(cbig,n,pchk_file,lines,nmessages,nutc,ntol,t00)
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crmax=maxval(abs(ccr))
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ishort=0
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if( crmax .gt. cmax ) ishort=1
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if( ishort .eq. 1 ) write(*,*) 'Short message detected'
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! Find 6 largest peaks
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do ipk=1, 6
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iloc=maxloc(abs(cc))
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396
lib/detectmsk40.f90
Normal file
396
lib/detectmsk40.f90
Normal file
@ -0,0 +1,396 @@
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subroutine detectmsk40(cbig,n,mycall,partnercall,lines,nmessages,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=10)
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character*4 rpt(0:63)
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character*6 mycall,partnercall
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character*22 hashmsg,msgreceived
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character*80 lines(100)
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character*40 pchk_file,gen_file
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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(0:63)
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integer indices(MAXSTEPS)
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integer ipeaks(10)
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integer*1 decoded(16)
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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 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 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 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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save df,first,cb,cbr,fs,nhashes,pi,twopi,dt,s8,s8r,rcw,pp,nmatchedfilter
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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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do i=0,30
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if( i.lt.5 ) then
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write(rpt(i),'(a1,i2.2,a1)') '-',abs(i-5)
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write(rpt(i+31),'(a2,i2.2,a1)') 'R-',abs(i-5)
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else
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write(rpt(i),'(a1,i2.2,a1)') '+',i-5
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write(rpt(i+31),'(a2,i2.2,a1)') 'R+',i-5
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endif
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enddo
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rpt(62)='RRR '
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rpt(63)='73 '
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do i=0,63
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hashmsg=trim(mycall)//' '//trim(partnercall)//' '//rpt(i)
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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,1023)
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enddo
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first=.false.
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endif
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! Temporarily hardwire filenames and init on every call
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pchk_file="peg-32-16-reg3.pchk"
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i=index(pchk_file,".pchk")
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gen_file=pchk_file(1:i-1)//".gen"
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call init_ldpc(trim(pchk_file)//char(0),trim(gen_file)//char(0))
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! Fill the detmet, detferr arrays
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nstepsize=48 ! 4ms steps
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nstep=(n-NPTS)/nstepsize
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detmet=0
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detmax=-999.99
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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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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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fdiff=(ihpk+deltah-ilpk-deltal)*df
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i2000=2000/df+1
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i4000=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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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),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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! ndet=15
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do ip=1,ndet
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! times(ip)=ip+0.012
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! snrs(ip)=-3.0
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! ferrs(ip)=0.0
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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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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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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(14,*) i,abs(ccr(i)),ddr(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(abs(ccr))
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ic1=iloc(1)
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iloc=maxloc(ddr)
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ic2=iloc(1)
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ipeaks(ipk)=ic1
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ccr(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=1,6
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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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if( ibb .le. 3 ) ibb=ibb-1
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if( ibb .gt. 3 ) ibb=ibb-7
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do id=1,1 ! 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(cb))
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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(cb))
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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(cb))
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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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! Final estimate of the carrier frequency - returned to the calling program
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fest=1500+ferr+ferr2
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do idf=0,0 ! 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*idf
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else
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deltaf=-2*(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(cb))
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phase0=atan2(imag(cca),real(cca))
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do ipha=1,1
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if( ipha.eq.2 ) phase0=phase0-20*pi/180.0
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if( ipha.eq.3 ) phase0=phase0+20*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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write(*,*) ip,id,nbadsync
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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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lratio(1:32)=exp(2.0*softbits(9:40)/(sigma*sigma))
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max_iterations=5
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max_dither=1
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call ldpc_decode(lratio,decoded,max_iterations,niterations,max_dither,ndither)
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nhashflag=0
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if( niterations .ge. 0 ) then
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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(i))
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enddo
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nrxrpt=iand(imsg,63)
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nrxhash=(imsg-nrxrpt)/64
|
||||
write(*,*) niterations,decoded,nrxrpt,nrxhash,nhashes(nrxrpt)
|
||||
if( nrxhash .eq. nhashes(nrxrpt) ) then
|
||||
nhashflag=1
|
||||
goto 999
|
||||
endif
|
||||
endif
|
||||
enddo ! phase loop
|
||||
enddo ! frame averaging loop
|
||||
enddo ! frequency dithering loop
|
||||
enddo ! slicer dither loop
|
||||
enddo ! time-sync correlation-peak loop
|
||||
enddo ! candidate loop
|
||||
999 continue
|
||||
msgreceived=' '
|
||||
if( nhashflag.eq.1 ) then
|
||||
nmessages=1
|
||||
write(msgreceived,'(a1,a,1x,a,a1,1x,a4)') "<",trim(mycall), &
|
||||
trim(partnercall),">",rpt(nrxrpt)
|
||||
write(lines(nmessages),1020) nutc,nsnr,t0,nint(fest),msgreceived
|
||||
1020 format(i6.6,i4,f5.1,i5,' & ',a22)
|
||||
|
||||
endif
|
||||
|
||||
return
|
||||
end subroutine detectmsk40
|
||||
@ -83,7 +83,7 @@ subroutine genmsk144(msg0,ichk,msgsent,i4tone,itype,pchk_file)
|
||||
if(message(1:1).eq.'<') then
|
||||
call genmsk40(message,msgsent,ichk,i4tone,itype)
|
||||
if(itype.lt.0) go to 999
|
||||
i4tone(39)=-40
|
||||
i4tone(41)=-40
|
||||
go to 999
|
||||
endif
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user