2020-06-17 11:50:28 -04:00
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module fst280_decode
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type :: fst280_decoder
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procedure(fst280_decode_callback), pointer :: callback
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contains
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procedure :: decode
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end type fst280_decoder
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abstract interface
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subroutine fst280_decode_callback (this,sync,snr,dt,freq,decoded,nap,qual)
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import fst280_decoder
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implicit none
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class(fst280_decoder), intent(inout) :: this
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real, intent(in) :: sync
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integer, intent(in) :: snr
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real, intent(in) :: dt
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real, intent(in) :: freq
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character(len=37), intent(in) :: decoded
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integer, intent(in) :: nap
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real, intent(in) :: qual
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end subroutine fst280_decode_callback
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end interface
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contains
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2020-06-17 14:17:03 -04:00
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subroutine decode(this,callback,iwave,nQSOProgress,nfqso, &
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nfa,nfb,ndepth,ntrperiod)
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use timer_module, only: timer
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use packjt77
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include 'fst280/fst280_params.f90'
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parameter (MAXCAND=100)
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class(fst280_decoder), intent(inout) :: this
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character*37 msg
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character*120 data_dir
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character*77 c77
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character*1 tr_designator
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complex, allocatable :: c2(:)
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complex, allocatable :: cframe(:)
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complex, allocatable :: c_bigfft(:) !Complex waveform
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real, allocatable :: r_data(:)
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real*8 fMHz
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real llr(280),llra(280),llrb(280),llrc(280),llrd(280)
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real candidates(100,3)
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real bitmetrics(328,4)
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integer hmod,ihdr(11)
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integer*1 apmask(280),cw(280)
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integer*1 hbits(328)
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integer*1 message101(101),message74(74)
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logical badsync,unpk77_success
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integer*2 iwave(300*12000)
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2020-06-17 20:31:54 -04:00
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2020-06-17 14:17:03 -04:00
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hmod=1 !### pass as arg ###
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Keff=91
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ndeep=3
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iwspr=0
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nmax=15*12000
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if(ntrperiod.eq.15) then
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nsps=800
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nmax=15*12000
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ndown=20/hmod
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if(hmod.eq.8) ndown=2
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else if(ntrperiod.eq.30) then
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nsps=1680
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nmax=30*12000
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ndown=42/hmod
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if(hmod.eq.4) ndown=10
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if(hmod.eq.8) ndown=5
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else if(ntrperiod.eq.60) then
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nsps=4000
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nmax=60*12000
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ndown=100/hmod
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if(hmod.eq.8) ndown=16
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else if(ntrperiod.eq.120) then
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nsps=8400
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nmax=120*12000
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ndown=200/hmod
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else if(ntrperiod.eq.300) then
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nsps=21504
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nmax=300*12000
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ndown=512/hmod
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end if
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nss=nsps/ndown
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fs=12000.0 !Sample rate
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fs2=fs/ndown
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nspsec=nint(fs2)
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dt=1.0/fs !Sample interval (s)
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dt2=1.0/fs2
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tt=nsps*dt !Duration of "itone" symbols (s)
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nfft1=2*int(nmax/2)
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nh1=nfft1/2
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allocate( r_data(1:nfft1+2) )
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allocate( c_bigfft(0:nfft1/2) )
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nfft2=nfft1/ndown
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allocate( c2(0:nfft2-1) )
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allocate( cframe(0:164*nss-1) )
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ngood=0
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ngoodsync=0
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npts=nmax
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fa=100.0
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fb=3500.0
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! The big fft is done once and is used for calculating the smoothed spectrum
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! and also for downconverting/downsampling each candidate.
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r_data(1:nfft1)=iwave(1:nfft1)
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r_data(nfft1+1:nfft1+2)=0.0
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call four2a(r_data,nfft1,1,-1,0)
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c_bigfft=cmplx(r_data(1:nfft1+2:2),r_data(2:nfft1+2:2))
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! Get first approximation of candidate frequencies
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call get_candidates_fst280(c_bigfft,nfft1,nsps,hmod,fs,fa,fb, &
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ncand,candidates)
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ndecodes=0
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isbest1=0
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isbest8=0
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fc21=fc0
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fc28=fc0
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do icand=1,ncand
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fc0=candidates(icand,1)
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xsnr=candidates(icand,2)
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! Downconvert and downsample a slice of the spectrum centered on the
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! rough estimate of the candidates frequency.
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! Output array c2 is complex baseband sampled at 12000/ndown Sa/sec.
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! The size of the downsampled c2 array is nfft2=nfft1/ndown
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call fst280_downsample(c_bigfft,nfft1,ndown,fc0,c2)
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call timer('sync280 ',0)
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do isync=0,1
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if(isync.eq.0) then
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fc1=0.0
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is0=nint(fs2)
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ishw=is0
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isst=4
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ifhw=10
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df=.1*8400/nsps
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else if(isync.eq.1) then
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fc1=fc28
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is0=isbest8
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ishw=4
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isst=1
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ifhw=10
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df=.02*8400/nsps
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endif
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smax1=0.0
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smax8=0.0
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do if=-ifhw,ifhw
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fc=fc1+df*if
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do istart=max(1,is0-ishw),is0+ishw,isst
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call sync_fst280(c2,istart,fc,hmod,1,nfft2,nss,fs2,sync1)
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call sync_fst280(c2,istart,fc,hmod,8,nfft2,nss,fs2,sync8)
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if(sync8.gt.smax8) then
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fc28=fc
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isbest8=istart
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smax8=sync8
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endif
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if(sync1.gt.smax1) then
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fc21=fc
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isbest1=istart
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smax1=sync1
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endif
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enddo
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enddo
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enddo
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call timer('sync280 ',1)
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if(smax8/smax1 .lt. 0.65 ) then
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fc2=fc21
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isbest=isbest1
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ntmax=4
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if(hmod.gt.1) ntmax=1
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ntmin=1
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njitter=2
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else
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fc2=fc28
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isbest=isbest8
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ntmax=4
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if(hmod.gt.1) ntmax=1
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ntmin=1
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njitter=2
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endif
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fc_synced = fc0 + fc2
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dt_synced = (isbest-fs2)*dt2 !nominal dt is 1 second so frame starts at sample fs2
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call fst280_downsample(c_bigfft,nfft1,ndown,fc_synced,c2)
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if(abs((isbest-fs2)/nss) .lt. 0.2 .and. abs(fc_synced-1500.0).lt.0.4) then
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ngoodsync=ngoodsync+1
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endif
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do ijitter=0,2
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if(ijitter.eq.0) ioffset=0
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if(ijitter.eq.1) ioffset=1
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if(ijitter.eq.2) ioffset=-1
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is0=isbest+ioffset
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if(is0.lt.0) cycle
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cframe=c2(is0:is0+164*nss-1)
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s2=sum(cframe*conjg(cframe))
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cframe=cframe/sqrt(s2)
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call get_fst280_bitmetrics(cframe,nss,hmod,bitmetrics,badsync)
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hbits=0
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where(bitmetrics(:,1).ge.0) hbits=1
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ns1=count(hbits( 1: 8).eq.(/0,0,0,1,1,0,1,1/))
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ns2=count(hbits( 9: 16).eq.(/0,1,0,0,1,1,1,0/))
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ns3=count(hbits(157:164).eq.(/0,0,0,1,1,0,1,1/))
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ns4=count(hbits(165:172).eq.(/0,1,0,0,1,1,1,0/))
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ns5=count(hbits(313:320).eq.(/0,0,0,1,1,0,1,1/))
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ns6=count(hbits(321:328).eq.(/0,1,0,0,1,1,1,0/))
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nsync_qual=ns1+ns2+ns3+ns4+ns5+ns6
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! if(nsync_qual.lt. 20) cycle
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scalefac=2.83
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llra( 1:140)=bitmetrics( 17:156, 1)
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llra(141:280)=bitmetrics(173:312, 1)
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llra=scalefac*llra
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llrb( 1:140)=bitmetrics( 17:156, 2)
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llrb(141:280)=bitmetrics(173:312, 2)
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llrb=scalefac*llrb
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llrc( 1:140)=bitmetrics( 17:156, 3)
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llrc(141:280)=bitmetrics(173:312, 3)
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llrc=scalefac*llrc
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llrd( 1:140)=bitmetrics( 17:156, 4)
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llrd(141:280)=bitmetrics(173:312, 4)
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llrd=scalefac*llrd
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apmask=0
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do itry=ntmax,ntmin,-1
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if(itry.eq.1) llr=llra
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if(itry.eq.2) llr=llrb
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if(itry.eq.3) llr=llrc
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if(itry.eq.4) llr=llrd
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dmin=0.0
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nharderrors=-1
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unpk77_success=.false.
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if(iwspr.eq.0) then
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maxosd=2
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call timer('d280_101',0)
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call decode280_101(llr,Keff,maxosd,ndeep,apmask,message101, &
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cw,ntype,nharderrors,dmin)
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call timer('d280_101',1)
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else
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maxosd=2
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call timer('d280_74 ',0)
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call decode280_74(llr,Keff,maxosd,ndeep,apmask,message74,cw, &
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ntype,nharderrors,dmin)
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call timer('d280_74 ',1)
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endif
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if(nharderrors .ge.0) then
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if(iwspr.eq.0) then
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write(c77,'(77i1)') message101(1:77)
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call unpack77(c77,0,msg,unpk77_success)
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else
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write(c77,'(50i1)') message74(1:50)
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c77(51:77)='000000000000000000000110000'
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call unpack77(c77,0,msg,unpk77_success)
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endif
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if(nharderrors .ge.0 .and. unpk77_success) then
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ngood=ngood+1
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write(*,1100) 0,nint(xsnr),dt_synced,nint(fc_synced),msg(1:22)
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1100 format(i6.6,i5,f5.1,i5,' `',1x,a22)
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goto 2002
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else
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cycle
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endif
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endif
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enddo ! metrics
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enddo ! istart jitter
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2002 continue
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enddo !candidate list
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write(*,1120)
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1120 format("<DecodeFinished>")
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return
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end subroutine decode
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subroutine sync_fst280(cd0,i0,f0,hmod,ncoh,np,nss,fs,sync)
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! Compute sync power for a complex, downsampled FST280 signal.
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include 'fst280/fst280_params.f90'
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complex cd0(0:np-1)
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complex, allocatable, save :: csync(:)
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complex, allocatable, save :: csynct(:)
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complex ctwk(8*nss)
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complex z1,z2,z3
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logical first
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integer hmod,isyncword(0:7)
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real f0save
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data isyncword/0,1,3,2,1,0,2,3/
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data first/.true./
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data f0save/0.0/
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save first,twopi,dt,fac,f0save
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p(z1)=(real(z1*fac)**2 + aimag(z1*fac)**2)**0.5 !Statement function for power
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if( first ) then
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allocate( csync(8*nss) )
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allocate( csynct(8*nss) )
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twopi=8.0*atan(1.0)
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dt=1/fs
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k=1
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phi=0.0
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do i=0,7
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dphi=twopi*hmod*(isyncword(i)-1.5)/real(nss)
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do j=1,nss
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csync(k)=cmplx(cos(phi),sin(phi))
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phi=mod(phi+dphi,twopi)
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k=k+1
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enddo
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enddo
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first=.false.
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fac=1.0/(8.0*nss)
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endif
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if(f0.ne.f0save) then
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dphi=twopi*f0*dt
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phi=0.0
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do i=1,8*nss
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ctwk(i)=cmplx(cos(phi),sin(phi))
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phi=mod(phi+dphi,twopi)
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enddo
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csynct=ctwk*csync
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f0save=f0
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endif
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i1=i0 !Costas arrays
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i2=i0+78*nss
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i3=i0+156*nss
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s1=0.0
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s2=0.0
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s3=0.0
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nsec=8/ncoh
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do i=1,nsec
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is=(i-1)*ncoh*nss
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z1=sum(cd0(i1+is:i1+is+ncoh*nss-1)*conjg(csynct(is+1:is+ncoh*nss)))
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z2=sum(cd0(i2+is:i2+is+ncoh*nss-1)*conjg(csynct(is+1:is+ncoh*nss)))
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z3=sum(cd0(i3+is:i3+is+ncoh*nss-1)*conjg(csynct(is+1:is+ncoh*nss)))
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|
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s1=s1+abs(z1)/(8*nss)
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s2=s2+abs(z2)/(8*nss)
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s3=s3+abs(z3)/(8*nss)
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enddo
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sync = s1+s2+s3
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return
|
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|
|
|
end subroutine sync_fst280
|
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|
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|
|
|
|
|
subroutine fst280_downsample(c_bigfft,nfft1,ndown,f0,c1)
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|
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|
|
! Output: Complex data in c(), sampled at 12000/ndown Hz
|
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|
|
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|
|
complex c_bigfft(0:nfft1/2)
|
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|
|
|
complex c1(0:nfft1/ndown-1)
|
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|
|
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|
|
df=12000.0/nfft1
|
|
|
|
|
i0=nint(f0/df)
|
|
|
|
|
c1(0)=c_bigfft(i0)
|
|
|
|
|
nfft2=nfft1/ndown
|
|
|
|
|
do i=1,nfft2/2
|
|
|
|
|
if(i0+i.le.nfft1/2) c1(i)=c_bigfft(i0+i)
|
|
|
|
|
if(i0-i.ge.0) c1(nfft2-i)=c_bigfft(i0-i)
|
|
|
|
|
enddo
|
|
|
|
|
c1=c1/nfft2
|
|
|
|
|
call four2a(c1,nfft2,1,1,1) !c2c FFT back to time domain
|
|
|
|
|
return
|
|
|
|
|
|
|
|
|
|
end subroutine fst280_downsample
|
|
|
|
|
|
|
|
|
|
subroutine get_candidates_fst280(c_bigfft,nfft1,nsps,hmod,fs,fa,fb, &
|
|
|
|
|
ncand,candidates)
|
|
|
|
|
|
|
|
|
|
complex c_bigfft(0:nfft1/2)
|
|
|
|
|
integer hmod
|
|
|
|
|
real candidates(100,3)
|
|
|
|
|
real s(18000)
|
|
|
|
|
real s2(18000)
|
|
|
|
|
data nfft1z/-1/
|
|
|
|
|
save nfft1z
|
|
|
|
|
|
|
|
|
|
nh1=nfft1/2
|
|
|
|
|
df1=fs/nfft1
|
|
|
|
|
baud=fs/nsps
|
|
|
|
|
df2=baud/2.0
|
|
|
|
|
nd=df1/df2
|
|
|
|
|
ndh=nd/2
|
|
|
|
|
ia=fa/df2
|
|
|
|
|
ib=fb/df2
|
|
|
|
|
s=0.
|
|
|
|
|
do i=ia,ib
|
|
|
|
|
j0=nint(i*df2/df1)
|
|
|
|
|
do j=j0-ndh,j0+ndh
|
|
|
|
|
s(i)=s(i) + real(c_bigfft(j))**2 + aimag(c_bigfft(j))**2
|
|
|
|
|
enddo
|
|
|
|
|
enddo
|
|
|
|
|
call pctile(s(ia:ib),ib-ia+1,30,base)
|
|
|
|
|
s=s/base
|
|
|
|
|
nh=hmod
|
|
|
|
|
do i=ia,ib
|
|
|
|
|
s2(i)=s(i-nh*3) + s(i-nh) +s(i+nh) +s(i+nh*3)
|
|
|
|
|
s2(i)=db(s2(i)) - 48.5
|
|
|
|
|
enddo
|
2020-06-18 09:14:11 -04:00
|
|
|
|
2020-06-17 14:17:03 -04:00
|
|
|
|
|
|
|
|
if(hmod.eq.1) thresh=-29.5 !### temporaray? ###
|
|
|
|
|
if(hmod.eq.2) thresh=-27.0
|
2020-06-18 09:14:11 -04:00
|
|
|
if(hmod.eq.4) thresh=-27.0
|
|
|
|
|
if(hmod.eq.8) thresh=-27.0
|
2020-06-17 14:17:03 -04:00
|
|
|
|
|
|
|
|
ncand=0
|
2020-06-18 09:14:11 -04:00
|
|
|
if(ia.lt.3) ia=3
|
|
|
|
|
if(ib.gt.18000-2) ib=18000-2
|
2020-06-17 14:17:03 -04:00
|
|
|
do i=ia,ib
|
2020-06-18 09:14:11 -04:00
|
|
|
if((s2(i).gt.s2(i-2)).and. &
|
|
|
|
|
(s2(i).gt.s2(i+2)).and. &
|
2020-06-17 14:17:03 -04:00
|
|
|
(s2(i).gt.thresh).and.ncand.lt.100) then
|
|
|
|
|
ncand=ncand+1
|
|
|
|
|
candidates(ncand,1)=df2*i
|
|
|
|
|
candidates(ncand,2)=s2(i)
|
|
|
|
|
endif
|
|
|
|
|
enddo
|
|
|
|
|
|
|
|
|
|
return
|
|
|
|
|
end subroutine get_candidates_fst280
|
2020-06-17 11:50:28 -04:00
|
|
|
|
|
|
|
|
end module fst280_decode
|
