mirror of https://github.com/saitohirga/WSJT-X.git
172 lines
4.6 KiB
Fortran
172 lines
4.6 KiB
Fortran
subroutine symspec(id,kbuf,kk,kkdone,nutc,newdat)
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! Compute spectra at four polarizations, using half-symbol steps.
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parameter (NSMAX=60*96000)
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integer*2 id(4,NSMAX,2)
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complex z
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real*8 ts,hsym
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include 'spcom.f90'
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include 'gcom2.f90'
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complex cx(NFFT),cy(NFFT) ! pad to 32k with zeros
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data kbuf0/-999/,n/0/
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save
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kkk=kk
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if(kbuf.eq.2) kkk=kk-5760000
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fac=0.0002
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hsym=2048.d0*96000.d0/11025.d0 !Samples per half symbol
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npts=hsym !Integral samples per half symbol
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ntot=322 !Half symbols per transmission
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! ntot=279 !Half symbols in 51.8 sec
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if(kbuf.ne.kbuf0 .or. ndiskdat.eq.1) then
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kkdone=0
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kbuf0=kbuf
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ts=1.d0 - hsym
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n=0
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do ip=1,4
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do i=1,NFFT
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szavg(ip,i)=0.
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enddo
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enddo
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! Get baseline power level for this minute
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n1=200 !Block size (somewhat arbitrary)
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n2=(kkk-kkdone)/n1 !Number of blocks
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k=0 !Starting place
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sqq=0.
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nsqq=0
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do j=1,n2
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sq=0.
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do i=1,n1 !Find power in each block
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k=k+1
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x1=id(1,k,kbuf)
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x2=id(2,k,kbuf)
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x3=id(3,k,kbuf)
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x4=id(4,k,kbuf)
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sq=sq + x1*x1 + x2*x2 + x3*x3 + x4*x4
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enddo
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if(sq.lt.n1*10000.) then !Find power in good blocks
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sqq=sqq+sq
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nsqq=nsqq+1
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endif
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enddo
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sqave=sqq/nsqq !Average power in good blocks
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nclip=0
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nz2=0
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endif
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if(nblank.ne.0) then
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! Apply final noise blanking
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n2=(kkk-kkdone)/n1
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k=kkdone
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do j=1,n2
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sq=0.
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do i=1,n1
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k=k+1
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x1=id(1,k,kbuf)
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x2=id(2,k,kbuf)
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x3=id(3,k,kbuf)
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x4=id(4,k,kbuf)
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sq=sq + x1*x1 + x2*x2 + x3*x3 + x4*x4
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enddo
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! If power in this block is excessive, blank it.
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if(sq.gt.1.5*sqave) then
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do i=k-n1+1,k
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id(1,i,kbuf)=0
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id(2,i,kbuf)=0
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id(3,i,kbuf)=0
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id(4,i,kbuf)=0
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enddo
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nclip=nclip+1
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endif
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enddo
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nz2=nz2+n2
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pctblank=nclip*100.0/nz2
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endif
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do nn=1,ntot
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i0=ts+hsym !Starting sample pointer
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if((i0+npts-1).gt.kkk) go to 998 !See if we have enough points
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i1=ts+2*hsym !Next starting sample pointer
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ts=ts+hsym !OK, update the exact sample pointer
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do i=1,npts !Copy data to FFT arrays
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xr=fac*id(1,i0+i,kbuf)
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xi=fac*id(2,i0+i,kbuf)
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cx(i)=cmplx(xr,xi)
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yr=fac*id(3,i0+i,kbuf)
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yi=fac*id(4,i0+i,kbuf)
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cy(i)=cmplx(yr,yi)
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enddo
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do i=npts+1,NFFT !Pad to 32k with zeros
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cx(i)=0.
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cy(i)=0.
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enddo
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call four2a(cx,NFFT,1,1,1) !Do the FFTs
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call four2a(cy,NFFT,1,1,1)
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n=n+1
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do i=1,NFFT !Save and accumulate power spectra
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sx=real(cx(i))**2 + aimag(cx(i))**2
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ssz(1,n,i)=sx ! Pol = 0
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szavg(1,i)=szavg(1,i) + sx
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z=cx(i) + cy(i)
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s45=0.5*(real(z)**2 + aimag(z)**2)
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ssz(2,n,i)=s45 ! Pol = 45
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szavg(2,i)=szavg(2,i) + s45
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sy=real(cy(i))**2 + aimag(cy(i))**2
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ssz(3,n,i)=sy ! Pol = 90
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szavg(3,i)=szavg(3,i) + sy
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z=cx(i) - cy(i)
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s135=0.5*(real(z)**2 + aimag(z)**2)
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ssz(4,n,i)=s135 ! Pol = 135
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szavg(4,i)=szavg(4,i) + s135
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z=cx(i)*conjg(cy(i))
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! Leif's formula:
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! ss5(n,i)=0.5*(sx+sy) + (real(z)**2 + aimag(z)**2 -
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! + sx*sy)/(sx+sy)
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! Leif's suggestion:
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! ss5(n,i)=max(sx,s45,sy,s135)
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! Linearly polarized component, from the Stokes parameters:
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q=sx - sy
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u=2.0*real(z)
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! v=2.0*aimag(z)
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ssz5(n,i)=0.707*sqrt(q*q + u*u)
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enddo
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! if(n.eq.ntot) then
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if(n.ge.279) then
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call move(ssz5,ss5,322*NFFT)
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call cs_lock('symspec')
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write(utcdata,1002) nutc
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1002 format(i4.4)
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call cs_unlock
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utcdata=utcdata(1:2)//':'//utcdata(3:4)
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newspec=1
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call move(ssz,ss,4*322*NFFT)
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call move(szavg,savg,4*NFFT)
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newdat=1
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ndecoding=1
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go to 999
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endif
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kkdone=i1-1
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nhsym=n
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call sleep_msec(0)
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enddo
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998 kkdone=i1-1
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999 continue
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return
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end subroutine symspec
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