mirror of https://github.com/saitohirga/WSJT-X.git
97 lines
2.3 KiB
Fortran
97 lines
2.3 KiB
Fortran
subroutine genjt8(message,iwave,nwave,nbit,msgsent)
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! Generate a JT8 wavefile.
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parameter (NMAX=60*12000) !Max length of wave file
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character*24 message !Message to be generated
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character*24 msgsent !Message as it will be received
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character cmode*5
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real*8 t,dt,phi,f,f0,dfgen,dphi,twopi,tsymbol
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integer*2 iwave(NMAX) !Generated wave file
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integer iu(3)
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integer gsym(372) !372 is needed for JT8 mode
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integer sent(144)
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integer ic8(8)
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data ic8/3,6,2,4,5,0,7,1/
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data nsps/4096/
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data twopi/6.283185307d0/
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save
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cmode='JT8' !### temp ? ###
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call srcenc(cmode,message,nbit,iu)
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! In JT8 mode, message length is always nbit=78
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if(nbit.ne.78) then
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print*,'genjt8, nbit=',nbit
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stop
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endif
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! Apply FEC and do the channel encoding
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call chenc(cmode,nbit,iu,gsym)
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! Remove source encoding, recover the human-readable message.
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call srcdec(cmode,nbit,iu,msgsent)
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! Insert 8x8 Costas array at beginning and end of array sent().
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sent(1:8)=ic8
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sent(135:142)=ic8
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! Insert two symbols after each Costas array to specify message length.
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if(nbit.eq.30) then
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sent(9)=2
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sent(10)=2
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sent(143)=2
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sent(144)=2
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else if(nbit.eq.48) then
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sent(9)=3
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sent(10)=3
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sent(143)=3
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sent(144)=3
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else
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sent(9)=6
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sent(10)=6
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sent(143)=6
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sent(144)=6
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endif
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! Insert the 3-bit data symbols
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sent(11:134)=gsym(1:124)
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! Use the four free symbols in 30-bit mode
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if(nbit.eq.30) then
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sent(121)=sent(20)
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sent(122)=sent(45)
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sent(123)=sent(70)
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sent(124)=sent(95)
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endif
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! Set up necessary constants
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nsym=144
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tsymbol=nsps/12000.d0
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dt=1.d0/12000.d0
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f0=1270.46d0
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dfgen=12000.d0/nsps
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t=0.d0
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phi=0.d0
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k=0
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j0=0
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ndata=(nsym*12000.d0*tsymbol)/2
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ndata=2*ndata
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do i=1,ndata
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t=t+dt
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j=int(t/tsymbol) + 1 !Symbol number, 1-nsym
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if(j.ne.j0) then
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f=f0
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k=k+1
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if(k.le.144) f=f0+(sent(k))*dfgen !### Fix need for this ###
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dphi=twopi*dt*f
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j0=j
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endif
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phi=phi+dphi
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iwave(i)=32767.0*sin(phi)
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enddo
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iwave(ndata+1:)=0
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nwave=ndata+6000 !0.5 s buffer before CW ID
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return
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end subroutine genjt8
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