subroutine cpolyfit(c,pp,id,maxn,aa,bb,zz) 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) 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 if(maxn.gt.0) then ! Fit sync info with a complex polynomial npts=n mode=0 chisqa0=1.e30 chisqb0=1.e30 nterms=maxn ! do nterms=1,maxn call polyfit4(x,yi,yi,npts,nterms,mode,aa,chisqa) call polyfit4(x,yq,yq,npts,nterms,mode,bb,chisqb) ! if(chisqa/chisqa0.ge.0.98 .and. chisqb/chisqb0.ge.0.98) exit chisqa0=chisqa chisqb0=chisqb ! enddo endif return end subroutine cpolyfit