subroutine qra64a(dd,nf1,nf2,nfqso,ntol,mycall_12,sync,nsnr,dtx,nfreq, & decoded,nft) use packjt parameter (NFFT=2*6912,NH=NFFT/2,NZ=5760) character decoded*22,mycall_12*12,mycall*6 character*1 mark(0:5),zplot(0:63) logical ltext integer icos7(0:6) integer ipk(1) integer jpk(1) integer dat4(12) real dd(60*12000) real s(NZ) real savg(NZ) real blue(0:25) real red0(NZ) real red(NZ) real x(NFFT) complex cx(0:NH) equivalence (x,cx) data icos7/2,5,6,0,4,1,3/ !Costas 7x7 pattern data mark/' ','.','-','+','X','$'/ common/qra64com/ss(NZ,194),s3(0:63,1:63),ccf(NZ,0:25) save decoded=' ' nft=99 nsnr=-30 nsps=6912 istep=nsps/2 nsteps=52*12000/istep - 2 ia=1-istep savg=0. df=12000.0/NFFT do j=1,nsteps ia=ia+istep ib=ia+nsps-1 x(1:nsps)=1.2e-4*dd(ia:ib) x(nsps+1:)=0.0 call four2a(x,nfft,1,-1,0) !r2c FFT do i=1,NZ s(i)=real(cx(i))**2 + aimag(cx(i))**2 enddo ss(1:NZ,j)=s savg=savg+s enddo savg=savg/nsteps fa=max(nf1,nfqso-ntol) fb=min(nf2,nfqso+ntol) ia=nint(fa/df) ib=nint(fb/df) call pctile(savg(ia),ib-ia+1,45,base) savg=savg/base - 1.0 ss=ss/base red0=0. fac=1.0/sqrt(21.0) sync=0. do if0=ia,ib red0(if0)=0. do j=0,25 t=-3.0 do n=0,6 i=if0 + 2*icos7(n) t=t + ss(i,1+2*n+j) + ss(i,1+2*n+j+78) + ss(i,1+2*n+j+154) enddo ccf(if0,j)=fac*t if(ccf(if0,j).gt.red0(if0)) then red0(if0)=ccf(if0,j) if(red0(if0).gt.sync) then sync=red0(if0) f0=if0*df dtx=j*istep/12000.0 - 1.0 i0=if0 j0=j endif endif enddo enddo red(ia:ib)=0. rewind 73 do i=ia+3,ib-3 r1=red0(i) red0(i)=0. r0=max(red0(i-3),red0(i-2),red0(i+2),red0(i+3)) red0(i)=r1 red(i)=max(0.0,r1-r0) write(73,3001) i*df,red(i),red0(i),r0 3001 format(4f12.3) enddo flush(73) write(17) ia,ib,red(ia:ib) close(17) if0=nint(f0/df) nfreq=nint(f0) blue(0:25)=ccf(if0,0:25) jpk=maxloc(blue) xpk=jpk(1) + 1.0 call slope(blue,26,xpk) ! Insist on at least 10 correct hard decisions in the 21 Costas bins. nhard=0 do n=0,6 ipk=maxloc(ss(i0:i0+63,1+j0+2*n)) - 1 i=abs(ipk(1)-2*icos7(n)) if(i.le.1) nhard=nhard+1 ipk=maxloc(ss(i0:i0+63,1+j0+2*n+78)) - 1 i=abs(ipk(1)-2*icos7(n)) if(i.le.1) nhard=nhard+1 ipk=maxloc(ss(i0:i0+63,1+j0+2*n+154)) - 1 i=abs(ipk(1)-2*icos7(n)) if(i.le.1) nhard=nhard+1 enddo ! print*,'a',nhard,nhard,nhard if(nhard.lt.6) go to 900 do i=0,63 k=i0 + 2*i jj=j0+13 do j=1,63 jj=jj+2 s3(i,j)=ss(k,jj) if(j.eq.32) jj=jj+14 !Skip over the middle Costas array enddo enddo if(sync.gt.1.0) nsnr=nint(10.0*log10(sync) - 38.0) ! if(sync.lt.12.8) go to 900 !### Temporary ### mycall=mycall_12(1:6) !### May need fixing ### call packcall(mycall,nmycall,ltext) call qra64_dec(s3,nmycall,dat4,irc) !Attempt decoding if(irc.ge.0) then call unpackmsg(dat4,decoded) !Unpack the user message call fmtmsg(decoded,iz) nft=100 + irc endif 900 return end subroutine qra64a