mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-09-17 10:46:33 -04:00
a9623703b3
changes on the C++ side. Basically works except that Tx audio has incorrect DT and audio is truncated at the end. Also, command line decoding using JT9 is not as sensitive as decoding from within WSJT-X.
88 lines
2.2 KiB
Fortran
88 lines
2.2 KiB
Fortran
subroutine getcandidates4(dd,fa,fb,syncmin,nfqso,maxcand,savg,candidate, &
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ncand,sbase)
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include 'ft4_params.f90'
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real s(NH1,NHSYM)
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real savg(NH1),savsm(NH1)
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real sbase(NH1)
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real x(NFFT1)
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real window(NFFT1)
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complex cx(0:NH1)
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real candidate(3,maxcand)
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real dd(NMAX)
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integer indx(NH1)
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integer ipk(1)
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equivalence (x,cx)
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logical first
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data first/.true./
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save first,window
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if(first) then
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first=.false.
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pi=4.0*atan(1.)
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window=0.
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call nuttal_window(window,NFFT1)
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endif
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! Compute symbol spectra, stepping by NSTEP steps.
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savg=0.
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tstep=NSTEP/12000.0
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df=12000.0/NFFT1
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fac=1.0/300.0
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do j=1,NHSYM
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ia=(j-1)*NSTEP + 1
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ib=ia+NFFT1-1
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if(ib.gt.NMAX) exit
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x=fac*dd(ia:ib)*window
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call four2a(x,NFFT1,1,-1,0) !r2c FFT
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do i=1,NH1
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s(i,j)=real(cx(i))**2 + aimag(cx(i))**2
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enddo
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savg=savg + s(1:NH1,j) !Average spectrum
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enddo
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savsm=0.
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do i=8,NH1-7
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savsm(i)=sum(savg(i-7:i+7))/15.
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enddo
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nfa=fa/df
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if(nfa.lt.1) nfa=1
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nfb=fb/df
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if(nfb.gt.nint(5000.0/df)) nfb=nint(5000.0/df)
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n300=300/df
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n2500=2500/df
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! np=nfb-nfa+1
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np=n2500-n300+1
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indx=0
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call indexx(savsm(n300:n2500),np,indx)
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xn=savsm(n300+indx(nint(0.3*np)))
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ncand=0
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if(xn.le.1.e-8) return
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savsm=savsm/xn
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! call ft4_baseline(savg,nfa,nfb,sbase)
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! savsm=savsm/sbase
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f_offset = -1.5*12000.0/NSPS
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do i=nfa+1,nfb-1
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if(savsm(i).ge.savsm(i-1) .and. savsm(i).ge.savsm(i+1) .and. &
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savsm(i).ge.syncmin) then
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den=savsm(i-1)-2*savsm(i)+savsm(i+1)
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del=0.
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if(den.ne.0.0) del=0.5*(savsm(i-1)-savsm(i+1))/den
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fpeak=(i+del)*df+f_offset
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if(fpeak.lt.0.0 .or. fpeak.gt.4910.0) cycle
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speak=savsm(i) - 0.25*(savsm(i-1)-savsm(i+1))*del
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ncand=ncand+1
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if(ncand.gt.maxcand) then
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ncand=maxcand
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exit
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endif
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candidate(1,ncand)=fpeak
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candidate(2,ncand)=-99.99
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candidate(3,ncand)=speak
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if(ncand.eq.maxcand) exit
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endif
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enddo
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return
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end subroutine getcandidates4
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