mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-22 20:28:42 -05:00
14cbb51e47
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7646 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
77 lines
2.4 KiB
Fortran
77 lines
2.4 KiB
Fortran
subroutine cpolyfit(c,pp,id,maxn,aa,bb,zz,nhardsync)
|
|
|
|
parameter (KK=84) !Information bits (72 + CRC12)
|
|
parameter (ND=168) !Data symbols: LDPC (168,84), r=1/2
|
|
parameter (NS=65) !Sync symbols (2 x 26 + Barker 13)
|
|
parameter (NR=3) !Ramp up/down
|
|
parameter (NN=NR+NS+ND) !Total symbols (236)
|
|
parameter (NSPS=16) !Samples per MSK symbol (16)
|
|
parameter (N2=2*NSPS) !Samples per OQPSK symbol (32)
|
|
parameter (N13=13*N2) !Samples in central sync vector (416)
|
|
parameter (NZ=NSPS*NN) !Samples in baseband waveform (3760)
|
|
parameter (NFFT1=4*NSPS,NH1=NFFT1/2)
|
|
|
|
complex c(0:NZ-1) !Complex waveform
|
|
complex zz(NS+ND) !Complex symbol values (intermediate)
|
|
complex z,z0
|
|
real x(NS),yi(NS),yq(NS) !For complex polyfit
|
|
real pp(2*NSPS) !Shaped pulse for OQPSK
|
|
real aa(20),bb(20) !Fitted polyco's
|
|
integer id(NS+ND) !NRZ values (+/-1) for Sync and Data
|
|
|
|
ib=NSPS-1
|
|
ib2=N2-1
|
|
n=0
|
|
do j=1,117 !First-pass demodulation
|
|
ia=ib+1
|
|
ib=ia+N2-1
|
|
zz(j)=sum(pp*c(ia:ib))/NSPS
|
|
if(abs(id(j)).eq.2) then !Save all sync symbols
|
|
n=n+1
|
|
x(n)=float(ia+ib)/NZ - 1.0
|
|
yi(n)=real(zz(j))*0.5*id(j)
|
|
yq(n)=aimag(zz(j))*0.5*id(j)
|
|
! write(54,1225) n,x(n),yi(n),yq(n)
|
|
!1225 format(i5,3f12.4)
|
|
endif
|
|
if(j.le.116) then
|
|
zz(j+117)=sum(pp*c(ia+NSPS:ib+NSPS))/NSPS
|
|
endif
|
|
enddo
|
|
|
|
aa=0.
|
|
bb=0.
|
|
nterms=0
|
|
chisqa=0.
|
|
chisqb=0.
|
|
if(maxn.gt.0) then
|
|
npts=n
|
|
mode=0
|
|
nterms=maxn
|
|
call polyfit4(x,yi,yi,npts,nterms,mode,aa,chisqa)
|
|
call polyfit4(x,yq,yq,npts,nterms,mode,bb,chisqb)
|
|
endif
|
|
|
|
nhardsync=0
|
|
do j=1,117
|
|
if(abs(id(j)).ne.2) cycle
|
|
xx=j*2.0/117.0 - 1.0
|
|
yii=1.
|
|
yqq=0.
|
|
if(nterms.gt.0) then
|
|
yii=aa(1)
|
|
yqq=bb(1)
|
|
do i=2,nterms
|
|
yii=yii + aa(i)*xx**(i-1)
|
|
yqq=yqq + bb(i)*xx**(i-1)
|
|
enddo
|
|
endif
|
|
z0=cmplx(yii,yqq)
|
|
z=zz(j)*conjg(z0)
|
|
p=real(z)
|
|
if(p*id(j).lt.0) nhardsync=nhardsync+1
|
|
enddo
|
|
|
|
return
|
|
end subroutine cpolyfit
|