WSJT-X/symspec.f
Joe Taylor 3b219465c7 Tick marks on waterfall displays.
Display percent of deopped packets.
Save all decodes to ALL65.txt.
Shift F12/F11 to inrecment/decrement fqso.
Save even/odd ip00 separately.


git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/map65@414 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2007-06-24 23:26:17 +00:00

88 lines
2.5 KiB
Fortran

subroutine symspec(id,nz,rxnoise,savg)
C Compute spectra at four polarizations, using half-symbol steps.
parameter (NFFT=32768)
parameter (NSMAX=60*96000)
integer*2 id(4,NSMAX)
real savg(4,NFFT)
complex cx(NFFT),cy(NFFT) ! pad to 32k with zeros
complex z
real*8 ts,hsym
common/spcom/ip0,ss(4,322,NFFT),ss5(322,NFFT)
! fac=1.e-4
! fac=1.7e-4
fac=0.0002 * 10.0**(0.05*(-rxnoise))
hsym=2048.d0*96000.d0/11025.d0 !Samples per half symbol
npts=hsym !Integral samples per half symbol
nsteps=322 !Half symbols per transmission
do ip=1,4
do i=1,NFFT
savg(ip,i)=0.
enddo
enddo
ts=1.d0 - hsym
do n=1,nsteps
ts=ts+hsym !Update exact sample pointer
i0=ts !Starting sample pointer
do i=1,npts !Copy data to FFT arrays
xr=fac*id(1,i0+i)
xi=fac*id(2,i0+i)
cx(i)=cmplx(xr,xi)
yr=fac*id(3,i0+i)
yi=fac*id(4,i0+i)
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)
do i=1,NFFT !Save and accumulate power spectra
sx=real(cx(i))**2 + aimag(cx(i))**2
ss(1,n,i)=sx ! Pol = 0
savg(1,i)=savg(1,i) + sx
z=cx(i) + cy(i)
s45=0.5*(real(z)**2 + aimag(z)**2)
ss(2,n,i)=s45 ! Pol = 45
savg(2,i)=savg(2,i) + s45
sy=real(cy(i))**2 + aimag(cy(i))**2
ss(3,n,i)=sy ! Pol = 90
savg(3,i)=savg(3,i) + sy
z=cx(i) - cy(i)
s135=0.5*(real(z)**2 + aimag(z)**2)
ss(4,n,i)=s135 ! Pol = 135
savg(4,i)=savg(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)
ss5(n,i)=0.707*sqrt(q*q + u*u)
enddo
enddo
return
end