subroutine get_ft4_bitmetrics(cd,bitmetrics,badsync) include 'ft4_params.f90' parameter (NSS=NSPS/NDOWN,NDMAX=NMAX/NDOWN) complex cd(0:NN*NSS-1) complex cs(0:3,NN) complex csymb(NSS) integer icos4a(0:3),icos4b(0:3),icos4c(0:3),icos4d(0:3) integer graymap(0:3) integer ip(1) logical one(0:255,0:7) ! 256 4-symbol sequences, 8 bits logical first logical badsync real bitmetrics(2*NN,3) real s2(0:255) real s4(0:3,NN) data icos4a/0,1,3,2/ data icos4b/1,0,2,3/ data icos4c/2,3,1,0/ data icos4d/3,2,0,1/ data graymap/0,1,3,2/ data first/.true./ save first,one if(first) then one=.false. do i=0,255 do j=0,7 if(iand(i,2**j).ne.0) one(i,j)=.true. enddo enddo first=.false. endif do k=1,NN i1=(k-1)*NSS csymb=cd(i1:i1+NSS-1) call four2a(csymb,NSS,1,-1,1) cs(0:3,k)=csymb(1:4) s4(0:3,k)=abs(csymb(1:4)) enddo ! Sync quality check is1=0 is2=0 is3=0 is4=0 badsync=.false. do k=1,4 ip=maxloc(s4(:,k)) if(icos4a(k-1).eq.(ip(1)-1)) is1=is1+1 ip=maxloc(s4(:,k+33)) if(icos4b(k-1).eq.(ip(1)-1)) is2=is2+1 ip=maxloc(s4(:,k+66)) if(icos4c(k-1).eq.(ip(1)-1)) is3=is3+1 ip=maxloc(s4(:,k+99)) if(icos4d(k-1).eq.(ip(1)-1)) is4=is4+1 enddo nsync=is1+is2+is3+is4 !Number of correct hard sync symbols, 0-16 if(nsync .lt. 8) then badsync=.true. return endif do nseq=1,3 !Try coherent sequences of 1, 2, and 4 symbols if(nseq.eq.1) nsym=1 if(nseq.eq.2) nsym=2 if(nseq.eq.3) nsym=4 nt=2**(2*nsym) do ks=1,NN-nsym+1,nsym !87+16=103 symbols. amax=-1.0 do i=0,nt-1 i1=i/64 i2=iand(i,63)/16 i3=iand(i,15)/4 i4=iand(i,3) if(nsym.eq.1) then s2(i)=abs(cs(graymap(i4),ks)) elseif(nsym.eq.2) then s2(i)=abs(cs(graymap(i3),ks)+cs(graymap(i4),ks+1)) elseif(nsym.eq.4) then s2(i)=abs(cs(graymap(i1),ks ) + & cs(graymap(i2),ks+1) + & cs(graymap(i3),ks+2) + & cs(graymap(i4),ks+3) & ) else print*,"Error - nsym must be 1, 2, or 4." endif enddo ipt=1+(ks-1)*2 if(nsym.eq.1) ibmax=1 if(nsym.eq.2) ibmax=3 if(nsym.eq.4) ibmax=7 do ib=0,ibmax bm=maxval(s2(0:nt-1),one(0:nt-1,ibmax-ib)) - & maxval(s2(0:nt-1),.not.one(0:nt-1,ibmax-ib)) if(ipt+ib.gt.2*NN) cycle bitmetrics(ipt+ib,nseq)=bm enddo enddo enddo bitmetrics(205:206,2)=bitmetrics(205:206,1) bitmetrics(201:204,3)=bitmetrics(201:204,2) bitmetrics(205:206,3)=bitmetrics(205:206,1) call normalizebmet(bitmetrics(:,1),2*NN) call normalizebmet(bitmetrics(:,2),2*NN) call normalizebmet(bitmetrics(:,3),2*NN) return end subroutine get_ft4_bitmetrics