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61 lines
1.4 KiB
Fortran
61 lines
1.4 KiB
Fortran
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subroutine sync66(c0,f0,jpk,sync)
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! Use the sync vector to find xdt (and improved f0 ?)
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PARAMETER (NMAX=15*6000)
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parameter (NSPS=960) !Samples per symbol at 6000 Hz
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complex c0(0:NMAX-1) !Complex data at 6000 S/s
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complex csync0(0:NSPS-1)
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complex csync1(0:NSPS-1)
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complex z
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integer b11(11) !Barker 11 code
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data b11/1,1,1,0,0,0,1,0,0,1,0/ !Barker 11 definition
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data mode66z/-1/
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save
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twopi=8.0*atan(1.0)
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baud=6000.0/NSPS
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dt=1.0/6000.0
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dphi0=twopi*f0**dt
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dphi1=twopi*(f0+baud)*dt
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phi0=0.
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phi1=0.
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do i=0,NSPS-1 !Compute csync for f0 and f0+baud
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csync0(i)=cmplx(cos(phi0),sin(phi0))
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csync1(i)=cmplx(cos(phi1),sin(phi1))
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phi0=phi0 + dphi0
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phi1=phi1 + dphi1
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if(phi0.gt.twopi) phi0=phi0-twopi
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if(phi1.gt.twopi) phi1=phi1-twopi
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enddo
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sqmax=0.
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jstep=NSPS/8
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do j0=0,6000,jstep
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sq=0.
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do k=1,22
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i=k
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if(i.gt.11) i=i-11
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j1=j0 + 4*(k-1)*NSPS
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if(b11(i).eq.0) then
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z=dot_product(c0(j1:j1+NSPS-1),csync0)
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else
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z=dot_product(c0(j1:j1+NSPS-1),csync1)
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endif
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z=0.001*z
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sq=sq + real(z)**2 + aimag(z)**2
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enddo
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write(52,3052) j0/6000.0,sq,j0,j1
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3052 format(f10.6,f12.3,2i8)
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if(sq.gt.smax) then
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smax=sq
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jpk=j0
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endif
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enddo
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sync=smax
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return
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end subroutine sync66
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