mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-03 07:51:16 -05:00
06291ab964
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/map65@334 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
91 lines
2.7 KiB
Fortran
91 lines
2.7 KiB
Fortran
subroutine spec2d65(dat,jz,nsym,flip,istart,f0,
|
|
+ ftrack,nafc,mode65,s2)
|
|
|
|
C Computes the spectrum for each of 126 symbols.
|
|
C NB: At this point, istart, f0, and ftrack are supposedly known.
|
|
C The JT65 signal has Sync bin + 2 guard bins + 64 data bins = 67 bins.
|
|
C We add 5 extra bins at top and bottom for drift, making 77 bins in all.
|
|
|
|
parameter (NMAX=2048) !Max length of FFTs
|
|
real dat(jz) !Raw data
|
|
real s2(77,126) !Spectra of all symbols
|
|
real s(77)
|
|
real ref(77)
|
|
real ps(77)
|
|
real x(NMAX)
|
|
real ftrack(126)
|
|
real*8 pha,dpha,twopi
|
|
complex cx(NMAX)
|
|
c complex work(NMAX)
|
|
include 'prcom.h'
|
|
equivalence (x,cx)
|
|
data twopi/6.28318530718d0/
|
|
save
|
|
|
|
C Peak up in frequency and time, and compute ftrack.
|
|
call ftpeak65(dat,jz,istart,f0,flip,pr,nafc,ftrack)
|
|
|
|
nfft=2048/mode65 !Size of FFTs
|
|
dt=2.0/11025.0
|
|
df=0.5*11025.0/nfft
|
|
call zero(ps,77)
|
|
k=istart-nfft
|
|
|
|
C NB: this could be done starting with array c3, in ftpeak65, instead
|
|
C of the dat() array. Would save some time this way ...
|
|
|
|
do j=1,nsym
|
|
call zero(s,77)
|
|
do m=1,mode65
|
|
k=k+nfft
|
|
if(k.ge.1 .and. k.le.(jz-nfft)) then
|
|
C Mix sync tone down to f=5*df (==> bin 6 of array cx, after FFT)
|
|
dpha=twopi*dt*(f0 + ftrack(j) - 5.0*df)
|
|
pha=0.0
|
|
do i=1,nfft
|
|
pha=pha+dpha
|
|
cx(i)=dat(k-1+i)*cmplx(cos(pha),-sin(pha))
|
|
enddo
|
|
|
|
call four2a(cx,nfft,1,-1,1)
|
|
do i=1,77
|
|
s(i)=s(i) + real(cx(i))**2 + aimag(cx(i))**2
|
|
enddo
|
|
|
|
else
|
|
call zero(s,77)
|
|
endif
|
|
enddo
|
|
call move(s,s2(1,j),77)
|
|
call add(ps,s,ps,77)
|
|
enddo
|
|
|
|
C Flatten the spectra by dividing through by the average of the
|
|
C "sync on" spectra, with the sync tone explicitly deleted.
|
|
nref=nsym/2
|
|
do i=1,77
|
|
C First we sum all the sync-on spectra:
|
|
ref(i)=0.
|
|
do j=1,nsym
|
|
if(flip*pr(j).gt.0.0) ref(i)=ref(i)+s2(i,j)
|
|
enddo
|
|
ref(i)=ref(i)/nref !Normalize
|
|
enddo
|
|
C Remove the sync tone itself:
|
|
base=0.25*(ref(1)+ref(2)+ref(10)+ref(11))
|
|
do i=3,9
|
|
ref(i)=base
|
|
enddo
|
|
|
|
C Now flatten the spectra for all the data symbols:
|
|
do i=1,77
|
|
fac=1.0/ref(i)
|
|
do j=1,nsym
|
|
s2(i,j)=fac*s2(i,j)
|
|
if(s2(i,j).eq.0.0) s2(i,j)=1.0 !### To fix problem in mfskprob
|
|
enddo
|
|
enddo
|
|
|
|
return
|
|
end
|