192 lines
5.8 KiB
Plaintext
192 lines
5.8 KiB
Plaintext
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subroutine fast9(id2,narg,line)
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! Decoder for "fast9" modes, JT9E to JT9H.
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parameter (NMAX=30*12000,NSAVE=500)
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integer*2 id2(0:NMAX)
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integer narg(0:14)
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integer*1 i1SoftSymbols(207)
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integer*1 i1save(207,NSAVE)
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integer indx(NSAVE)
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integer*8 count0,count1,clkfreq
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real s1(720000) !To reserve space. Logically s1(nq,jz)
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real s2(240,340) !Symbol spectra at quarter-symbol steps
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real ss2(0:8,85) !Folded symbol spectra
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real ss3(0:7,69) !Folded spectra without sync symbols
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real s(1500)
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real ccfsave(NSAVE)
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real t0save(NSAVE)
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real t1save(NSAVE)
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real freqSave(NSAVE)
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real t(6)
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character*22 msg !Decoded message
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character*80 line(100)
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data nsubmode0/-1/,ntot/0/
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save s1,nsubmode0,ntot
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! Parameters from GUI are in narg():
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nutc=narg(0) !UTC
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npts=min(narg(1),NMAX) !Number of samples in id2 (12000 Hz)
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nsubmode=narg(2) !0=A 1=B 2=C 3=D 4=E 5=F 6=G 7=H
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if(nsubmode.lt.4) go to 900
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newdat=narg(3) !1==> new data, compute symbol spectra
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minsync=narg(4) !Lower sync limit
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npick=narg(5)
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t0=0.001*narg(6)
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t1=0.001*narg(7)
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maxlines=narg(8) !Max # of decodes to return to caller
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nmode=narg(9)
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nrxfreq=narg(10) !Targer Rx audio frequency (Hz)
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ntol=narg(11) !Search range, +/- ntol (Hz)
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tmid=npts*0.5/12000.0
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line(1:100)(1:1)=char(0)
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s=0
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s2=0
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nsps=60 * 2**(7-nsubmode) !Samples per sysbol
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nfft=2*nsps !FFT size
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nh=nfft/2
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nq=nfft/4
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istep=nsps/4 !Symbol spectra at quarter-symbol steps
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jz=npts/istep
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df=12000.0/nfft !FFT bin width
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db1=db(2500.0/df)
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nfa=max(200,nrxfreq-ntol) !Lower frequency limit
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nfb=min(nrxfreq+ntol,2500) !Upper frequency limit
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nline=0
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t=0.
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if(newdat.eq.1 .or. nsubmode.ne.nsubmode0) then
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call system_clock(count0,clkfreq)
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call spec9f(id2,npts,nsps,s1,jz,nq) !Compute symbol spectra, s1
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call system_clock(count1,clkfreq)
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t(1)=t(1)+float(count1-count0)/float(clkfreq)
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endif
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nsubmode0=nsubmode
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tmsg=nsps*85.0/12000.0
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limit=2000
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nlen0=0
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i1=0
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i2=0
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ccfsave=0.
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do ilength=1,14
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nlen=1.4142136**(ilength-1)
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if(nlen.gt.jz/340) nlen=jz/340
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if(nlen.eq.nlen0) cycle
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nlen0=nlen
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db0=db(float(nlen))
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jlen=nlen*340
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jstep=jlen/4 !### Is this about right? ###
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if(nsubmode.ge.6) jstep=jlen/2
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do ja=1,jz-jlen,jstep
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jb=ja+jlen-1
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call system_clock(count0,clkfreq)
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call foldspec9f(s1,nq,jz,ja,jb,s2) !Fold symbol spectra into s2
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call system_clock(count1,clkfreq)
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t(2)=t(2)+float(count1-count0)/float(clkfreq)
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! Find sync; put sync'ed symbol spectra into ss2 and ss3
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! Might want to do a peakup in DT and DF, then re-compute symbol spectra.
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call system_clock(count0,clkfreq)
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call sync9f(s2,nq,nfa,nfb,ss2,ss3,lagpk,ipk,ccfbest)
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call system_clock(count1,clkfreq)
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t(3)=t(3)+float(count1-count0)/float(clkfreq)
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i1=i1+1
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if(ccfbest.lt.30.0) cycle
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call system_clock(count0,clkfreq)
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call softsym9f(ss2,ss3,i1SoftSymbols) !Compute soft symbols
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call system_clock(count1,clkfreq)
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t(4)=t(4)+float(count1-count0)/float(clkfreq)
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i2=i2+1
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ccfsave(i2)=ccfbest
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i1save(1:207,i2)=i1SoftSymbols
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t0=(ja-1)*istep/12000.0
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t1=(jb-1)*istep/12000.0
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t0save(i2)=t0
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t1save(i2)=t1
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freq=ipk*df
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freqSave(i2)=freq
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enddo
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enddo
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nsaved=i2
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ccfsave(1:nsaved)=-ccfsave(1:nsaved)
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call system_clock(count0,clkfreq)
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indx=0
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call indexx(ccfsave,nsaved,indx)
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call system_clock(count1,clkfreq)
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t(5)=t(5)+float(count1-count0)/float(clkfreq)
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ccfsave(1:nsaved)=-ccfsave(1:nsaved)
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do iter=1,2
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! do isave=1,nsaved
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do isave=1,50
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i2=indx(isave)
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if(i2.lt.1 .or. i2.gt.nsaved) cycle !### Why needed? ###
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t0=t0save(i2)
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t1=t1save(i2)
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if(iter.eq.1 .and. t1.lt.tmid) cycle
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if(iter.eq.2 .and. t1.ge.tmid) cycle
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ccfbest=ccfsave(i2)
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i1SoftSymbols=i1save(1:207,i2)
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freq=freqSave(i2)
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call system_clock(count0,clkfreq)
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call jt9fano(i1SoftSymbols,limit,nlim,msg) !Invoke Fano decoder
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call system_clock(count1,clkfreq)
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t(6)=t(6)+float(count1-count0)/float(clkfreq)
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i=t0*12000.0
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kz=(t1-t0)/0.02
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smax=0.
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do k=1,kz
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sq=0.
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do n=1,240
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i=i+1
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x=id2(i)
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sq=sq+x*x
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enddo
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s(k)=sq/240.
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smax=max(s(k),smax)
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enddo
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call pctile(s,kz,35,base)
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snr=smax/(1.1*base) - 1.0
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nsnr=-20
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if(snr.gt.0.0) nsnr=nint(db(snr))
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! write(72,3002) nutc,iter,isave,nlen,tmid,t0,t1,ccfbest, &
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! nint(freq),nlim,msg
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!3002 format(i6.6,i1,i4,i3,4f6.1,i5,i7,1x,a22)
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if(msg.ne.' ') then
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! Display multiple decodes only if they differ:
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do n=1,nline
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if(index(line(n),msg).gt.1) go to 100
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enddo
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!### Might want to use decoded message to get a complete estimate of S/N.
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nline=nline+1
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write(line(nline),1000) nutc,nsnr,t0,nint(freq),msg,char(0)
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1000 format(i6.6,i4,f5.1,i5,1x,'@ ',1x,a22,a1)
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ntot=ntot+1
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! write(70,5001) nsaved,isave,nline,maxlines,ntot,nutc,msg
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!5001 format(5i5,i7.6,1x,a22)
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if(nline.ge.maxlines) go to 900
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endif
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100 continue
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enddo
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enddo
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900 continue
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! write(*,6001) t,t(6)/sum(t)
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!6001 format(7f10.3)
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return
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end subroutine fast9
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