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https://github.com/saitohirga/WSJT-X.git
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23ab527e4d
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@2603 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
98 lines
2.9 KiB
Fortran
98 lines
2.9 KiB
Fortran
subroutine genjt9(message,minutes,lwave,msgsent,d8,iwave,nwave)
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! Encodes a "JT9-minutes" message and returns array d7(85) of tone
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! values in the range 0-8. If lwave is true, also returns a generated
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! waveform in iwave(nwave), at 12000 samples per second.
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parameter (NMAX=1800*12000) !Max length of wave file
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character*22 message !Message to be generated
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character*22 msgsent !Message as it will be received
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real*8 dt,phi,f,f0,dfgen,dphi,twopi
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integer*2 iwave(NMAX) !Generated wave file
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integer*4 d0(12) !72-bit message as 6-bit words
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integer*1 d1(72) !72 single bits
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integer*4 d2(9) !72 bits as 8-bit words
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integer*1 d3(9) !72 bits as 8-bit bytes
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integer*1 d4(206) !Encoded information-carrying bits
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integer*1 d5(206) !Bits from d4, after interleaving
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integer*4 d6(69) !Symbols from d5, values 0-7
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integer*4 d7(69) !Gray-coded symbols, values 0-7
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integer*4 d8(85) !Channel symbols including sync, values 0-8
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logical lwave
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integer isync(85)
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data isync/ &
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1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0, &
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1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0, &
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0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0, &
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0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0, &
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1,0,0,0,1/
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data twopi/6.283185307179586476d0/
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save
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call packmsg(message,d0) !Pack message into 12 6-bit bytes
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call unpackbits(d0,12,6,d1) !Unpack into 72 bits
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nbits=72
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nbytes=9
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call packbits(d1,nbits,8,d2) !Pack into 9 8-bit words
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do i=1,9
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if(d2(i).lt.128) d3(i)=d2(i)
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if(d2(i).ge.128) d3(i)=d2(i)-256
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enddo
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call encode232(d3,nbytes,d4) !Convolutional code, K=32, r=1/2
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nsym2=206
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call interleave9(d4,1,d5)
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call packbits(d5,nsym2,3,d6)
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call graycode(d6,69,1,d7)
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! Insert sync symbols (ntone=0) and add 1 to the data-tone numbers.
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j=0
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do i=1,85
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if(isync(i).eq.1) then
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d8(i)=0
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else
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j=j+1
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d8(i)=d7(j)+1
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endif
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enddo
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nwave=0
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if(lwave) then
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nsps=0
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if(minutes.eq.1) nsps=6912
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if(minutes.eq.2) nsps=15360
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if(minutes.eq.5) nsps=40960
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if(minutes.eq.10) nsps=82944
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if(minutes.eq.30) nsps=250880
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if(nsps.eq.0) stop 'Bad value for minutes in genjt9.'
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! Set up necessary constants
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dt=1.d0/12000.d0
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f0=1500.d0
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dfgen=12000.d0/nsps
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phi=0.d0
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i=0
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k=0
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do j=1,85
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f=f0 +d7(j)*dfgen
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dphi=twopi*dt*f
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do i=1,nsps
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phi=phi+dphi
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if(phi.gt.twopi) phi=phi-twopi
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xphi=phi
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k=k+1
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iwave(k)=32767.0*sin(xphi)
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enddo
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enddo
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nwave=85*nsps
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endif
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call unpackmsg(d0,msgsent)
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return
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end subroutine genjt9
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