mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-17 09:31:59 -05:00
c2ceb42b28
svn+ssh://svn.berlios.de/svnroot/repos/wsjt/WSJT/branches/linux merged into svn+ssh://svn.berlios.de/svnroot/repos/wsjt/trunk git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/trunk@155 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
88 lines
2.2 KiB
Fortran
88 lines
2.2 KiB
Fortran
subroutine sync(y1,y2,y3,y4,npts,jpk,baud,bauderr)
|
|
|
|
C Input data are in the y# arrays: detected sigs in four tone-channels,
|
|
C before decimation by NSPD.
|
|
|
|
parameter (NSPD=25)
|
|
real y1(npts)
|
|
real y2(npts)
|
|
real y3(npts)
|
|
real y4(npts)
|
|
real zf(NSPD)
|
|
real tmp1
|
|
real tmp2
|
|
complex csum
|
|
integer nsum(NSPD)
|
|
real z(65538) !Ready for FSK110
|
|
complex cz(0:32768)
|
|
equivalence (z,cz)
|
|
data twopi/6.283185307/
|
|
|
|
do i=1,NSPD
|
|
zf(i)=0.0
|
|
nsum(i)=0
|
|
enddo
|
|
|
|
do i=1,npts
|
|
a1=max(y1(i),y2(i),y3(i),y4(i)) !Find the largest one
|
|
|
|
if(a1.eq.y1(i)) then !Now find 2nd largest
|
|
a2=max(y2(i),y3(i),y4(i))
|
|
else if(a1.eq.y2(i)) then
|
|
a2=max(y1(i),y3(i),y4(i))
|
|
else if(a1.eq.y3(i)) then
|
|
a2=max(y1(i),y2(i),y4(i))
|
|
else
|
|
a2=max(y1(i),y2(i),y3(i))
|
|
endif
|
|
|
|
z(i)=1.e-6*(a1-a2) !Subtract 2nd from 1st
|
|
j=mod(i-1,NSPD)+1
|
|
zf(j)=zf(j)+z(i)
|
|
nsum(j)=nsum(j)+1
|
|
enddo
|
|
|
|
n=log(float(npts))/log(2.0)
|
|
nfft=2**(n+1)
|
|
call zero(z(npts+1),nfft-npts)
|
|
call xfft(z,nfft)
|
|
|
|
C Now find the apparent baud rate.
|
|
df=11025.0/nfft
|
|
zmax=0.
|
|
ia=391.0/df !Was 341/df
|
|
ib=491.0/df !Was 541/df
|
|
do i=ia,ib
|
|
z(i)=real(cz(i))**2 + aimag(cz(i))**2
|
|
if(z(i).gt.zmax) then
|
|
zmax=z(i)
|
|
baud=df*i
|
|
endif
|
|
enddo
|
|
|
|
C Find phase of signal at 441 Hz.
|
|
csum=0.
|
|
do j=1,NSPD
|
|
pha=j*twopi/NSPD
|
|
csum=csum+zf(j)*cmplx(cos(pha),-sin(pha))
|
|
enddo
|
|
tmp1=aimag(csum)
|
|
tmp2=real(csum)
|
|
pha=-atan2(tmp1,tmp2)
|
|
jpk=nint(NSPD*pha/twopi)
|
|
if(jpk.lt.1) jpk=jpk+NSPD
|
|
|
|
C The following is nearly equivalent to the above. I don't know which
|
|
C (if either) is better.
|
|
c zfmax=-1.e30
|
|
c do j=1,NSPD
|
|
c if(zf(j).gt.zfmax) then
|
|
c zfmax=zf(j)
|
|
c jpk2=j
|
|
c endif
|
|
c enddo
|
|
|
|
bauderr=(baud-11025.0/NSPD)/df !Baud rate error, in bins
|
|
return
|
|
end
|