45 lines
1.2 KiB
Plaintext
45 lines
1.2 KiB
Plaintext
subroutine genbpsk(id,f00,ndiff,nref,c)
|
|
|
|
parameter (ND=121) !Data symbols: LDPC (120,60), r=1/2
|
|
parameter (NN=ND) !Total symbols (121)
|
|
parameter (NSPS=28800) !Samples per symbol at 12000 sps
|
|
parameter (NZ=NSPS*NN) !Samples in waveform (3456000)
|
|
|
|
complex c(0:NZ-1) !Complex waveform
|
|
real*8 twopi,dt,fs,baud,f0,dphi,phi
|
|
integer id(NN) !Encoded NRZ data (values +/-1)
|
|
integer ie(NN) !Differentially encoded data
|
|
|
|
f0=f00
|
|
twopi=8.d0*atan(1.d0)
|
|
fs=12000.d0
|
|
dt=1.0/fs
|
|
baud=1.d0/(NSPS*dt)
|
|
|
|
if(ndiff.ne.0) then
|
|
ie(1)=1 !First bit is always 1
|
|
do i=2,NN !Differentially encode
|
|
ie(i)=id(i)*ie(i-1)
|
|
enddo
|
|
endif
|
|
|
|
! Generate the BPSK waveform
|
|
phi=0.d0
|
|
k=-1
|
|
do j=1,NN
|
|
dphi=twopi*f0*dt
|
|
x=id(j)
|
|
if(ndiff.ne.0) x=ie(j) !Differential
|
|
if(nref.ne.0) x=1.0 !Generate reference carrier
|
|
do i=1,NSPS
|
|
k=k+1
|
|
phi=phi+dphi
|
|
if(phi.gt.twopi) phi=phi-twopi
|
|
xphi=phi
|
|
c(k)=x*cmplx(cos(xphi),sin(xphi))
|
|
enddo
|
|
enddo
|
|
|
|
return
|
|
end subroutine genbpsk
|