WSJT-X/lib/ft8/foxgen.f90

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Fortran
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subroutine foxgen()
! Called from MainWindow::foxTxSequencer() to generate the Tx waveform in
! FT8 Fox mode. The Tx message can contain up to 5 "slots", each carrying
! its own FT8 signal.
! Encoded messages can be of the form "HoundCall FoxCall rpt" (a standard FT8
! message with i3bit=0) or "HoundCall_1 RR73; HoundCall_2 <FoxCall> rpt",
! a new message type with i3bit=1. The waveform is generated with
! fsample=48000 Hz; it is compressed to reduce the PEP-to-average power ratio,
! with (currently disabled) filtering afterware to reduce spectral growth.
! Input message information is provided in character array cmsg(5), in
! common/foxcom/. The generated wave(NWAVE) is passed back in the same
! common block.
parameter (NN=79,ND=58,NSPS=4*1920)
parameter (NWAVE=NN*NSPS,NFFT=614400,NH=NFFT/2)
character*40 cmsg
character*37 msg,msgsent
integer itone(79)
integer*1 msgbits(77),msgbits2
integer*1, target:: i1Msg8BitBytes(11)
integer*1, target:: mycall
real x(NFFT)
real*8 dt,twopi,f0,fstep,dfreq,phi,dphi
complex cx(0:NH)
common/foxcom/wave(NWAVE),nslots,nfreq,i3bit(5),cmsg(5),mycall(12)
common/foxcom2/itone2(NN),msgbits2(77)
equivalence (x,cx),(y,cy)
fstep=60.d0
dfreq=6.25d0
dt=1.d0/48000.d0
twopi=8.d0*atan(1.d0)
irpt=0
nplot=0
wave=0.
do n=1,nslots
msg=cmsg(n)(1:37)
call genft8_174_91(msg,i3,n3,msgsent,msgbits,itone)
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! print*,'Foxgen:',n,msg,msgsent,i3,n3
! write(*,'(77i1)') msgbits
! Make copies of itone() and msgbits() for ft8sim
itone2=itone
msgbits2=msgbits
f0=nfreq + fstep*(n-1)
phi=0.d0
k=0
do j=1,NN
f=f0 + dfreq*itone(j)
dphi=twopi*f*dt
do ii=1,NSPS
k=k+1
phi=phi+dphi
xphi=phi
wave(k)=wave(k)+sin(xphi)
enddo
enddo
enddo
kz=k
peak1=maxval(abs(wave))
wave=wave/peak1
! call plotspec(1,wave) !Plot the spectrum
! Apply compression
! rms=sqrt(dot_product(wave,wave)/kz)
! wave=wave/rms
! do i=1,NWAVE
! wave(i)=h1(wave(i))
! enddo
! peak2=maxval(abs(wave))
! wave=wave/peak2
! call plotspec(2,wave) !Plot the spectrum
width=50.0
call foxfilt(nslots,nfreq,width,wave)
peak3=maxval(abs(wave))
wave=wave/peak3
! nadd=1000
! j=0
! do i=1,NWAVE,nadd
! sx=dot_product(wave(i:i+nadd-1),wave(i:i+nadd-1))
! j=j+1
! write(30,3001) j,sx/nadd
!3001 format(i8,f12.6)
! enddo
! call plotspec(3,wave) !Plot the spectrum
return
end subroutine foxgen
! include 'plotspec.f90'