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https://github.com/saitohirga/WSJT-X.git
synced 2024-11-03 16:01:18 -05:00
fcd068b7c4
Tweak decoding parameters in sync9. git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@3268 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
160 lines
4.6 KiB
Fortran
160 lines
4.6 KiB
Fortran
subroutine symspec(k,ntrperiod,nsps,ingain,nb,nbslider,pxdb,s,red, &
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df3,ihsym,nzap,slimit,lstrong,npts8)
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! Input:
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! k pointer to the most recent new data
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! ntrperiod T/R sequence length, minutes
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! nsps samples per symbol, at 12000 Hz
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! ndiskdat 0/1 to indicate if data from disk
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! nb 0/1 status of noise blanker (off/on)
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! nbslider NB setting, 0-100
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! Output:
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! pxdb power (0-60 dB)
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! s() spectrum for waterfall display
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! red() first cut at JT9 sync amplitude
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! ihsym index number of this half-symbol (1-184)
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! nzap number of samples zero'ed by noise blanker
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! slimit NB scale adjustment
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! lstrong true if strong signal at this freq
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parameter (NMAX=1800*12000) !Total sample intervals per 30 minutes
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parameter (NDMAX=1800*1500) !Sample intervals at 1500 Hz rate
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parameter (NSMAX=22000) !Max length of saved spectra
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parameter (NFFT1=1024)
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parameter (NFFT2=1024,NFFT2A=NFFT2/8)
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parameter (MAXFFT3=32768)
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real*4 s(NSMAX),w3(MAXFFT3)
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real*4 x0(NFFT1),x1(NFFT1)
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real*4 x2(NFFT1+105)
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real*4 ssum(NSMAX)
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real*4 red(NSMAX)
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complex cx(0:MAXFFT3-1)
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logical*1 lstrong(0:1023) !Should be (0:512)
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integer*2 id2
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complex c0
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common/jt9com/ss(184,NSMAX),savg(NSMAX),c0(NDMAX),id2(NMAX),nutc,ndiskdat, &
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ntr,mousefqso,newdat,nfa,nfb,ntol,kin,nzhsym,nsynced,ndecoded
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data rms/999.0/,k0/99999999/,ntrperiod0/0/,nfft3z/0/
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save
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if(ntrperiod.eq.1) nfft3=2048
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if(ntrperiod.eq.2) nfft3=2048
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if(ntrperiod.eq.5) nfft3=6144
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if(ntrperiod.eq.10) nfft3=12288
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if(ntrperiod.eq.30) nfft3=32768
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jstep=nsps/16 !Step size = half-symbol in c0()
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if(k.gt.NMAX) go to 999
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if(k.lt.nfft3) then
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ihsym=0
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go to 999 !Wait for enough samples to start
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endif
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if(nfft3.ne.nfft3z) then !New nfft3, compute window
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pi=4.0*atan(1.0)
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if(ntrperiod.eq.1) then !Compute window for nfft3 spectrun
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do i=1,nfft3
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xx=float(i-1)/(nfft3-1)
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w3(i)=0.40897 -0.5*cos(2.0*pi*xx) + 0.09103*cos(4.0*pi*xx)
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! w3(i)=0.355768 - 0.487306*cos(2.0*pi*xx) + 0.144232*cos(4.0*pi*xx) &
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! - 0.012604*cos(6.0*pi*xx)
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enddo
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else
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do i=1,nfft3
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w3(i)=2.0*(sin(i*pi/nfft3))**2 !Window for nfft3 spectrum
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enddo
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endif
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nfft3z=nfft3
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endif
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if(k.lt.k0) then !Start a new data block
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ja=0
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ssum=0.
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ihsym=0
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k1=0
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k8=0
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x2=0.
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if(ndiskdat.eq.0) then
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id2(k+1:)=0
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c0=0. !This is necessary to prevent "ghosts". Not sure why.
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endif
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endif
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k0=k
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nzap=0
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sigmas=1.0*(10.0**(0.01*nbslider)) + 0.7
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peaklimit=sigmas*max(10.0,rms)
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px=0.
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nwindow=2
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! nwindow=0 !### No windowing ###
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kstep1=NFFT1
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if(nwindow.ne.0) kstep1=NFFT1/2
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fac=2.0/NFFT1
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nblks=(k-k1)/kstep1
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gain=10.0**(0.05*ingain)
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do nblk=1,nblks
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do i=1,NFFT1
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x0(i)=gain*id2(k1+i)
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enddo
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call timf2(x0,k,NFFT1,nwindow,nb,peaklimit,x1, &
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slimit,lstrong,px,nzap)
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! Mix at 1500 Hz, lowpass at +/-750 Hz, and downsample to 1500 Hz complex.
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x2(106:105+kstep1)=x1(1:kstep1)
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call fil3(x2,kstep1+105,c0(k8+1),n2)
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x2(1:105)=x1(kstep1-104:kstep1) !Save 105 trailing samples
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k1=k1+kstep1
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k8=k8+kstep1/8
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enddo
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npts8=k8
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ja=ja+jstep !Index of first sample
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nsum=nblks*kstep1 - nzap
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if(nsum.le.0) nsum=1
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rms=sqrt(px/nsum)
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pxdb=0.
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if(rms.gt.0.0) pxdb=20.0*log10(rms)
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if(pxdb.gt.60.0) pxdb=60.0
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do i=0,nfft3-1 !Copy data into cx
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j=ja+i-(nfft3-1)
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cx(i)=0.
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if(j.ge.1 .and. j.le.NDMAX) cx(i)=c0(j)
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enddo
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if(ihsym.lt.184) ihsym=ihsym+1
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cx(0:nfft3-1)=w3(1:nfft3)*cx(0:nfft3-1) !Apply window w3
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call four2a(cx,nfft3,1,1,1) !Third FFT (forward)
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n=min(184,ihsym)
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df3=1500.0/nfft3 !JT9-a: 0.732 Hz = 0.42 * tone spacing
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i0=nint(-500.0/df3)
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iz=min(NSMAX,nint(1000.0/df3))
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fac=(1.0/nfft3)**2
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do i=1,iz
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j=i0+i-1
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if(j.lt.0) j=j+nfft3
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sx=fac*(real(cx(j))**2 + aimag(cx(j))**2)
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ss(n,i)=sx
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ssum(i)=ssum(i) + sx
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s(i)=sx
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enddo
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999 continue
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fac00=0.35
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npct=20
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call pctile(s,iz,npct,xmed0)
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fac0=fac00/max(xmed0,0.006)
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s(1:iz)=fac0*s(1:iz)
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call pctile(ssum,iz,npct,xmed1)
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fac1=fac00/max(xmed1,0.006*ihsym)
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savg(1:iz)=fac1*ssum(1:iz)
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savg(iz+1:iz+20)=savg(iz)
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call redsync(ss,ntrperiod,ihsym,iz,red)
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return
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end subroutine symspec
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