WSJT-X/symspec.f90

128 lines
3.8 KiB
Fortran

subroutine symspec(id,kbuf,kk,kkdone,nutc,newdat)
! Compute spectra at four polarizations, using half-symbol steps.
parameter (NSMAX=60*96000)
integer*2 id(4,NSMAX,2)
complex z
real*8 ts,hsym
include 'spcom.f90'
include 'gcom2.f90'
complex cx(NFFT),cy(NFFT) ! pad to 32k with zeros
data kbuf0/-999/,n/0/
save
kkk=kk
if(kbuf.eq.2) kkk=kk-5760000
! if(ndebug.gt.0) write(*,4001) 'A',nutc,mod(int(sec_midn()),60), &
! kbuf,kk,kkk,kkdone
!4001 format(a1,i5.4,2i3,3i9,i5)
if(ndebug.eq.2) write(29,3001) nutc,mod(int(sec_midn()),60), &
kbuf,kk,kkdone,ndecoding,newdat,n
3001 format('s1:',i5.4,i3.2,i5,2i10,2i3,i5)
fac=0.0002
hsym=2048.d0*96000.d0/11025.d0 !Samples per half symbol
npts=hsym !Integral samples per half symbol
ntot=322 !Half symbols per transmission
! ntot=279 !Half symbols in 51.8 sec
if(kbuf.ne.kbuf0 .or. ndiskdat.eq.1) then
kkdone=0
kbuf0=kbuf
ts=1.d0 - hsym
n=0
do ip=1,4
do i=1,NFFT
szavg(ip,i)=0.
enddo
enddo
endif
do nn=1,ntot
i0=ts+hsym !Starting sample pointer
if((i0+npts-1).gt.kkk) go to 998 !See if we have enough points
i1=ts+2*hsym !Next starting sample pointer
ts=ts+hsym !OK, update the exact sample pointer
do i=1,npts !Copy data to FFT arrays
xr=fac*id(1,i0+i,kbuf)
xi=fac*id(2,i0+i,kbuf)
cx(i)=cmplx(xr,xi)
yr=fac*id(3,i0+i,kbuf)
yi=fac*id(4,i0+i,kbuf)
cy(i)=cmplx(yr,yi)
enddo
do i=npts+1,NFFT !Pad to 32k with zeros
cx(i)=0.
cy(i)=0.
enddo
call four2a(cx,NFFT,1,1,1) !Do the FFTs
call four2a(cy,NFFT,1,1,1)
n=n+1
do i=1,NFFT !Save and accumulate power spectra
sx=real(cx(i))**2 + aimag(cx(i))**2
ssz(1,n,i)=sx ! Pol = 0
szavg(1,i)=szavg(1,i) + sx
z=cx(i) + cy(i)
s45=0.5*(real(z)**2 + aimag(z)**2)
ssz(2,n,i)=s45 ! Pol = 45
szavg(2,i)=szavg(2,i) + s45
sy=real(cy(i))**2 + aimag(cy(i))**2
ssz(3,n,i)=sy ! Pol = 90
szavg(3,i)=szavg(3,i) + sy
z=cx(i) - cy(i)
s135=0.5*(real(z)**2 + aimag(z)**2)
ssz(4,n,i)=s135 ! Pol = 135
szavg(4,i)=szavg(4,i) + s135
z=cx(i)*conjg(cy(i))
! Leif's formula:
! ss5(n,i)=0.5*(sx+sy) + (real(z)**2 + aimag(z)**2 -
! + sx*sy)/(sx+sy)
! Leif's suggestion:
! ss5(n,i)=max(sx,s45,sy,s135)
! Linearly polarized component, from the Stokes parameters:
q=sx - sy
u=2.0*real(z)
! v=2.0*aimag(z)
ssz5(n,i)=0.707*sqrt(q*q + u*u)
enddo
! if(n.eq.ntot) then
if(n.ge.279) then
call move(ssz5,ss5,322*NFFT)
write(utcdata,1002) nutc
1002 format(i4.4)
utcdata=utcdata(1:2)//':'//utcdata(3:4)
newspec=1
call move(ssz,ss,4*322*NFFT)
call move(szavg,savg,4*NFFT)
newdat=1
ndecoding=1
go to 999
endif
kkdone=i1-1
nhsym=n
call sleep_msec(0)
enddo
998 kkdone=i1-1
999 continue
! if(ndebug.gt.0) write(*,4001) 'B',nutc,mod(int(sec_midn()),60), &
! kbuf,kk,kkk,kkdone,n
if(ndebug.eq.2) write(29,3002) nutc,mod(int(sec_midn()),60), &
kbuf,kk,kkdone,ndecoding,newdat,n
3002 format('s2:',i5.4,i3.2,i5,2i10,2i3,i5)
return
end subroutine symspec