module q65_decode type :: q65_decoder procedure(q65_decode_callback), pointer :: callback contains procedure :: decode end type q65_decoder abstract interface subroutine q65_decode_callback (this,nutc,snr1,nsnr,dt,freq, & decoded,nap,ntrperiod) import q65_decoder implicit none class(q65_decoder), intent(inout) :: this integer, intent(in) :: nutc real, intent(in) :: snr1 integer, intent(in) :: nsnr real, intent(in) :: dt real, intent(in) :: freq character(len=37), intent(in) :: decoded integer, intent(in) :: nap integer, intent(in) :: ntrperiod end subroutine q65_decode_callback end interface contains subroutine decode(this,callback,iwave,nutc,ntrperiod,nsubmode,nfqso, & ntol,ndepth,lclearave,emedelay,mycall,hiscall,hisgrid,nQSOprogress, & ncontest,lapcqonly) ! Decodes Q65 signals ! Input: iwave Raw data, i*2 ! nutc UTC for time-tagging the decode ! ntrperiod T/R sequence length (s) ! nsubmode Tone-spacing indicator, 0-4 for A-E ! nfqso Target signal frequency (Hz) ! ntol Search range around nfqso (Hz) ! ndepth Optional decoding level ! Output: sent to the callback routine for display to user use timer_module, only: timer use packjt77 use, intrinsic :: iso_c_binding use q65 !Shared variables parameter (NMAX=300*12000) !Max TRperiod is 300 s class(q65_decoder), intent(inout) :: this procedure(q65_decode_callback) :: callback character(len=12) :: mycall, hiscall !Used for AP decoding character(len=6) :: hisgrid character*37 decoded !Decoded message character*77 c77 character*78 c78 integer*2 iwave(NMAX) !Raw data real, allocatable :: dd(:) !Raw data integer dat4(13) !Decoded message as 12 6-bit integers integer apmask1(78),apsymbols1(78) integer dgen(13) logical lclearave,lapcqonly,unpk77_success complex, allocatable :: c00(:) !Analytic signal, 6000 Sa/s complex, allocatable :: c0(:) !Analytic signal, 6000 Sa/s idec=-1 mode_q65=2**nsubmode npts=ntrperiod*12000 nfft1=ntrperiod*12000 nfft2=ntrperiod*6000 if(lclearave) nsave=0 allocate(dd(npts)) allocate (c00(0:nfft1-1)) allocate (c0(0:nfft1-1)) if(ntrperiod.eq.15) then nsps=1800 else if(ntrperiod.eq.30) then nsps=3600 else if(ntrperiod.eq.60) then nsps=7200 else if(ntrperiod.eq.120) then nsps=16000 else if(ntrperiod.eq.300) then nsps=41472 else stop 'Invalid TR period' endif baud=12000.0/nsps df1=12000.0/nfft1 this%callback => callback nFadingModel=1 ibwa=max(1,int(1.8*log(baud*mode_q65)) + 2) ibwb=min(10,ibwa+4) if(iand(ndepth,3).eq.3) then ibwa=max(1,ibwa-1) ibwb=min(10,ibwb+1) endif ! Set up the codewords for full-AP list decoding call q65_set_list(mycall,hiscall,hisgrid,codewords,ncw) dgen=0 call q65_enc(dgen,codewords) !Initialize the Q65 codec call timer('q65_dec0',0) call q65_dec0(nutc,iwave,ntrperiod, & nfqso,ntol,ndepth,lclearave,emedelay,xdt,f0,snr1,width,dat4, & snr2,idec) call timer('q65_dec0',1) if(idec.ge.0) then xdt1=xdt !We have a list-decode result f1=f0 go to 100 endif if(snr1.lt.2.8) then xdt1=0. !No reliable sync, abandon decoding attempt f1=0. go to 100 endif jpk0=(xdt+1.0)*6000 !Index of nominal start of signal if(ntrperiod.le.30) jpk0=(xdt+0.5)*6000 !For shortest sequences if(jpk0.lt.0) jpk0=0 fac=1.0/32767.0 dd=fac*iwave(1:npts) call ana64(dd,npts,c00) !Convert to complex c00() at 6000 Sa/s ! Generate ap symbols as in FT8 call ft8apset(mycall,hiscall,ncontest,apsym0,aph10) where(apsym0.eq.-1) apsym0=0 ! Main decoding loop starts here npasses=2 if(nQSOprogress.eq.5) npasses=3 if(lapcqonly) npasses=1 iaptype=0 do ipass=0,npasses apmask=0 !Try first with no AP information apsymbols=0 if(ipass.ge.1) then ! Subsequent passes use AP information appropiate for nQSOprogress call q65_ap(nQSOprogress,ipass,ncontest,lapcqonly,iaptype, & apsym0,apmask1,apsymbols1) write(c78,1050) apmask1 1050 format(78i1) read(c78,1060) apmask 1060 format(13b6.6) write(c78,1050) apsymbols1 read(c78,1060) apsymbols endif call timer('q65loops',0) call q65_loops(c00,npts/2,nsps/2,nsubmode,ndepth,jpk0, & xdt,f0,iaptype,xdt1,f1,snr2,dat4,idec) call timer('q65loops',1) if(idec.ge.0) go to 100 !Successful decode, we're done enddo ! There was no single-transmission decode. if(iand(ndepth,16).eq.16) then ! Try for an average decode. call timer('q65_avg2',0) ! call q65_avg2(ntrperiod,baud,nsubmode,nQSOprogress,lapcqonly, & ! codewords,ncw,xdt,f0,snr2,dat4,idec) call timer('q65_avg2',1) endif 100 decoded=' ' if(idec.gt.0) then ! ------------------------------------------------------ ! idec Meaning ! ------------------------------------------------------ ! -1: No decode ! 1: Decode with AP for "MyCall DxCall ?" ! 2: Decode without AP information ! 3: Decode with AP for "CQ ? ?" ! 4: Decode with AP for "MyCall ? ?" ! ------------------------------------------------------ ! Second digit (if any) is number of sequences averaged. ! ------------------------------------------------------ ! Unpack decoded message for display to user write(c77,1000) dat4(1:12),dat4(13)/2 1000 format(12b6.6,b5.5) call unpack77(c77,0,decoded,unpk77_success) !Unpack to get msgsent nsnr=nint(snr2) call this%callback(nutc,snr1,nsnr,xdt1,f1,decoded,idec,ntrperiod) call q65_clravg else ! Report snr1, even if no decode. nsnr=db(snr1) - 35.0 idec=-1 call this%callback(nutc,snr1,nsnr,xdt1,f1,decoded, & idec,ntrperiod) endif return end subroutine decode end module q65_decode