module ft8_a7 parameter(MAXDEC=100) ! For the following three arrays ! First index i=decode number in this sequence ! Second index j=0 or 1 for even or odd sequence ! Third index k=0 or 1 for previous or current tally for this j real dt0(MAXDEC,0:1,0:1) !dt0(i,j,k) real f0(MAXDEC,0:1,0:1) !f0(i,j,k) character*37 msg0(MAXDEC,0:1,0:1) !msg0(i,j,k) integer itone_a7(79) integer jseq !even=0, odd=1 integer ndec(0:1,0:1) !ndec(j,k) data ndec/4*0/,jseq/0/ contains subroutine ft8_a7_save(nutc,dt,f,msg) use packjt77 character*37 msg,msg1 character*13 w(19) character*4 g4 integer nw(19) logical isgrid4 ! Statement function: isgrid4(g4)=(len_trim(g4).eq.4 .and. & ichar(g4(1:1)).ge.ichar('A') .and. ichar(g4(1:1)).le.ichar('R') .and. & ichar(g4(2:2)).ge.ichar('A') .and. ichar(g4(2:2)).le.ichar('R') .and. & ichar(g4(3:3)).ge.ichar('0') .and. ichar(g4(3:3)).le.ichar('9') .and. & ichar(g4(4:4)).ge.ichar('0') .and. ichar(g4(4:4)).le.ichar('9')) if(index(msg,'/').ge.1 .or. index(msg,'<').ge.1) go to 999 call split77(msg,nwords,nw,w) !Parse msg into words if(nwords.lt.1) go to 999 if(w(1)(1:3).eq.'CQ_') go to 999 j=mod(nutc/5,2) !j is 0 or 1 for odd/even sequence jseq=j ! Add this decode to current table for this sequence ndec(j,1)=ndec(j,1)+1 !Number of decodes in this sequence i=ndec(j,1) !i is index of a new table entry if(i.ge.MAXDEC-1) return !Prevent table overflow dt0(i,j,1)=dt !Save dt in table f0(i,j,1)=f !Save f in table msg0(i,j,1)=trim(w(1))//' '//trim(w(2)) !Save "call_1 call_2" if(w(1)(1:3).eq.'CQ ' .and. nw(2).le.2) then msg0(i,j,1)='CQ '//trim(w(2))//' '//trim(w(3)) !Save "CQ DX Call_2" endif msg1=msg0(i,j,1) !Message without grid nn=len(trim(msg1)) !Message length without grid ! Include grid as part of message if(isgrid4(w(nwords))) msg0(i,j,1)=trim(msg0(i,j,1))//' '//trim(w(nwords)) ! If a transmission at this frequency with message fragment "call_1 call_2" ! was decoded in the previous sequence, flag it as "DO NOT USE" because ! we have already decoded and subtracted that station's next transmission. call split77(msg0(i,j,1),nwords,nw,w) !Parse msg into words do i=1,ndec(j,0) if(f0(i,j,0).le.-98.0) cycle i2=index(msg0(i,j,0),' '//trim(w(2))) if(abs(f-f0(i,j,0)).le.3.0 .and. i2.ge.3) then f0(i,j,0)=-98.0 !Flag as "do not use" for a potential a7 decode endif enddo 999 return end subroutine ft8_a7_save subroutine ft8_a7d(dd0,newdat,call_1,call_2,grid4,xdt,f1,xbase,nharderrors,dmin, & msg37,xsnr) ! Examine the raw data in dd0() for possible "a7" decodes. use crc use timer_module, only: timer use packjt77 include 'ft8_params.f90' parameter(NP2=2812) character*37 msg37,msg,msgsent,msgbest character*12 call_1,call_2 character*4 grid4 real a(5) real s8(0:7,NN) real s2(0:511) real dmm(206) real bmeta(174),bmetb(174),bmetc(174),bmetd(174) real llra(174),llrb(174),llrc(174),llrd(174) !Soft symbols real dd0(15*12000) real ss(9) real rcw(174) integer*1 cw(174) integer*1 msgbits(77) integer*1 nxor(174),hdec(174) integer itone(NN) integer icos7(0:6),ip(1) logical one(0:511,0:8) integer graymap(0:7) integer iloc(1) complex cd0(0:3199) complex ctwk(32) complex csymb(32) complex cs(0:7,NN) logical std_1,std_2 logical first,newdat data icos7/3,1,4,0,6,5,2/ !Sync array data first/.true./ data graymap/0,1,3,2,5,6,4,7/ save one if(first) then one=.false. do i=0,511 do j=0,8 if(iand(i,2**j).ne.0) one(i,j)=.true. enddo enddo first=.false. endif call stdcall(call_1,std_1) if(call_1(1:3).eq.'CQ ') std_1=.true. call stdcall(call_2,std_2) fs2=12000.0/NDOWN dt2=1.0/fs2 twopi=8.0*atan(1.0) delfbest=0. ibest=0 call timer('ft8_down',0) call ft8_downsample(dd0,newdat,f1,cd0) !Mix f1 to baseband and downsample call timer('ft8_down',1) i0=nint((xdt+0.5)*fs2) !Initial guess for start of signal smax=0.0 do idt=i0-10,i0+10 !Search over +/- one quarter symbol call sync8d(cd0,idt,ctwk,0,sync) !NB: ctwk not used here if(sync.gt.smax) then smax=sync ibest=idt endif enddo ! Peak up in frequency smax=0.0 do ifr=-5,5 !Search over +/- 2.5 Hz delf=ifr*0.5 dphi=twopi*delf*dt2 phi=0.0 do i=1,32 ctwk(i)=cmplx(cos(phi),sin(phi)) phi=mod(phi+dphi,twopi) enddo call sync8d(cd0,ibest,ctwk,1,sync) if( sync .gt. smax ) then smax=sync delfbest=delf endif enddo a=0.0 a(1)=-delfbest call twkfreq1(cd0,NP2,fs2,a,cd0) f1=f1+delfbest !Improved estimate of DF call timer('ft8_down',0) call ft8_downsample(dd0,.false.,f1,cd0) !Mix f1 to baseband and downsample call timer('ft8_down',1) smax=0.0 do idt=-4,4 !Search over +/- one quarter symbol call sync8d(cd0,ibest+idt,ctwk,0,sync) ss(idt+5)=sync enddo smax=maxval(ss) iloc=maxloc(ss) ibest=iloc(1)-5+ibest xdt=(ibest-1)*dt2 - 0.5 sync=smax do k=1,NN i1=ibest+(k-1)*32 csymb=cmplx(0.0,0.0) if( i1.ge.0 .and. i1+31 .le. NP2-1 ) csymb=cd0(i1:i1+31) call four2a(csymb,32,1,-1,1) cs(0:7,k)=csymb(1:8)/1e3 s8(0:7,k)=abs(csymb(1:8)) enddo ! sync quality check is1=0 is2=0 is3=0 do k=1,7 ip=maxloc(s8(:,k)) if(icos7(k-1).eq.(ip(1)-1)) is1=is1+1 ip=maxloc(s8(:,k+36)) if(icos7(k-1).eq.(ip(1)-1)) is2=is2+1 ip=maxloc(s8(:,k+72)) if(icos7(k-1).eq.(ip(1)-1)) is3=is3+1 enddo ! hard sync sum - max is 21 nsync=is1+is2+is3 ! if(nsync .le. 6) return ! bail out do nsym=1,3 nt=2**(3*nsym) do ihalf=1,2 do k=1,29,nsym if(ihalf.eq.1) ks=k+7 if(ihalf.eq.2) ks=k+43 amax=-1.0 do i=0,nt-1 i1=i/64 i2=iand(i,63)/8 i3=iand(i,7) if(nsym.eq.1) then s2(i)=abs(cs(graymap(i3),ks)) elseif(nsym.eq.2) then s2(i)=abs(cs(graymap(i2),ks)+cs(graymap(i3),ks+1)) elseif(nsym.eq.3) then s2(i)=abs(cs(graymap(i1),ks)+cs(graymap(i2),ks+1)+cs(graymap(i3),ks+2)) else print*,"Error - nsym must be 1, 2, or 3." endif enddo i32=1+(k-1)*3+(ihalf-1)*87 if(nsym.eq.1) ibmax=2 if(nsym.eq.2) ibmax=5 if(nsym.eq.3) ibmax=8 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(i32+ib .gt.174) cycle if(nsym.eq.1) then bmeta(i32+ib)=bm den=max(maxval(s2(0:nt-1),one(0:nt-1,ibmax-ib)), & maxval(s2(0:nt-1),.not.one(0:nt-1,ibmax-ib))) if(den.gt.0.0) then cm=bm/den else ! erase it cm=0.0 endif bmetd(i32+ib)=cm elseif(nsym.eq.2) then bmetb(i32+ib)=bm elseif(nsym.eq.3) then bmetc(i32+ib)=bm endif enddo enddo enddo enddo call normalizebmet(bmeta,174) call normalizebmet(bmetb,174) call normalizebmet(bmetc,174) call normalizebmet(bmetd,174) scalefac=2.83 llra=scalefac*bmeta llrb=scalefac*bmetb llrc=scalefac*bmetc llrd=scalefac*bmetd ! apmag=maxval(abs(llra))*1.01 MAXMSG=206 pbest=0. dmin=1.e30 nharderrors=-1 do imsg=1,MAXMSG msg=trim(call_1)//' '//trim(call_2) i=imsg if(call_1(1:3).eq.'CQ ' .and. i.ne.5) msg='QU1RK '//trim(call_2) if(.not.std_1) then if(i.eq.1 .or. i.ge.6) msg='<'//trim(call_1)//'> '//trim(call_2) if(i.ge.2 .and. i.le.4) msg=trim(call_1)//' <'//trim(call_2)//'>' else if(.not.std_2) then if(i.le.4 .or. i.eq.6) msg='<'//trim(call_1)//'> '//trim(call_2) if(i.ge.7) msg=trim(call_1)//' <'//trim(call_2)//'>' endif j0=len(trim(msg))+2 if(i.eq.2) msg(j0:j0+2)='RRR' if(i.eq.3) msg(j0:j0+3)='RR73' if(i.eq.4) msg(j0:j0+1)='73' if(i.eq.5) then if(std_2) then msg='CQ '//trim(call_2) if(call_1(3:3).eq.'_') msg=trim(call_1)//' '//trim(call_2) if(grid4.ne.'RR73') msg=trim(msg)//' '//grid4 endif if(.not.std_2) msg='CQ '//trim(call_2) endif if(i.eq.6 .and. std_2) msg(j0:j0+3)=grid4 if(i.ge.7) then isnr = -50 + (i-7)/2 if(iand(i,1).eq.1) then write(msg(j0:j0+2),'(i3.2)') isnr if(msg(j0:j0).eq.' ') msg(j0:j0)='+' else write(msg(j0:j0+3),'("R",i3.2)') isnr if(msg(j0+1:j0+1).eq.' ') msg(j0+1:j0+1)='+' endif endif i3=-1 n3=-1 call genft8(msg,i3,n3,msgsent,msgbits,itone) !Source-encode this message call encode174_91(msgbits,cw) !Get codeword for this message rcw=2*cw-1 pow=0.0 do i=1,79 pow=pow+s8(itone(i),i)**2 enddo hdec=0 where(llra.ge.0.0) hdec=1 nxor=ieor(hdec,cw) da=sum(nxor*abs(llra)) hdec=0 where(llrb.ge.0.0) hdec=1 nxor=ieor(hdec,cw) dbb=sum(nxor*abs(llrb)) hdec=0 where(llrc.ge.0.0) hdec=1 nxor=ieor(hdec,cw) dc=sum(nxor*abs(llrc)) hdec=0 where(llrd.ge.0.0) hdec=1 nxor=ieor(hdec,cw) dd=sum(nxor*abs(llrd)) dm=min(da,dbb,dc,dd) dmm(imsg)=dm if(dm.lt.dmin) then dmin=dm msgbest=msgsent pbest=pow if(dm.eq.da) then nharderrors=count((2*cw-1)*llra.lt.0.0) else if(dm.eq.dbb) then nharderrors=count((2*cw-1)*llrb.lt.0.0) else if(dm.eq.dc) then nharderrors=count((2*cw-1)*llrc.lt.0.0) else if(dm.eq.dd) then nharderrors=count((2*cw-1)*llrd.lt.0.0) endif endif enddo ! imsg iloc=minloc(dmm) dmm(iloc(1))=1.e30 iloc=minloc(dmm) dmin2=dmm(iloc(1)) xsnr=-24. arg=pbest/xbase/3.0e6-1.0 if(arg.gt.0.0) xsnr=max(-24.0,db(arg)-27.0) ! write(41,3041) nharderrors,dmin,dmin2,dmin2/dmin,xsnr,trim(msgbest) !3041 format(i3,2f7.1,f7.2,f7.1,1x,a) if(dmin.gt.100.0 .or. dmin2/dmin.lt.1.3) nharderrors=-1 msg37=msgbest if(msg37(1:3).eq.'CQ ' .and. std_2 .and. grid4.eq.' ') nharderrors=-1 if(msg37(1:6).eq.'QU1RK ') nharderrors=-1 return end subroutine ft8_a7d end module ft8_a7