86 lines
2.7 KiB
Fortran
86 lines
2.7 KiB
Fortran
subroutine genjs8(msg,mygrid,bcontest,i3bit,msgsent,msgbits,itone)
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! Encode an JS8 message, producing array itone().
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use crc
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use packjt
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include 'js8_params.f90'
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parameter (KK=87) !Information bits (75 + CRC12)
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parameter (ND=58) !Data symbols
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parameter (NS=21) !Sync symbols (3 @ Costas 7x7)
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parameter (NN=NS+ND) !Total channel symbols (79)
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character*68 alphabet
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character*22 msg,msgsent
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character*6 mygrid
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character*87 cbits
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logical bcontest,checksumok
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integer*4 i4Msg6BitWords(12) !72-bit message as 6-bit words
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integer*1 msgbits(KK),codeword(3*ND)
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integer*1, target:: i1Msg8BitBytes(11)
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integer itone(NN)
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integer icos7a(0:6), icos7b(0:6), icos7c(0:6)
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if(NCOSTAS.eq.1) then
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icos7a = (/4,2,5,6,1,3,0/) !Beginning Costas 7x7 tone pattern
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icos7b = (/4,2,5,6,1,3,0/) !Middle Costas 7x7 tone pattern
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icos7c = (/4,2,5,6,1,3,0/) !End Costas 7x7 tone pattern
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else
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icos7a = (/0,6,2,3,5,4,1/) !Beginning Costas 7x7 tone pattern
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icos7b = (/1,5,0,2,3,6,4/) !Middle Costas 7x7 tone pattern
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icos7c = (/2,5,0,6,4,1,3/) !End Costas 7x7 tone pattern
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endif
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alphabet='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-+/?.'
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itype=6
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do i=1,12
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v=index(alphabet, msg(i:i))
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if(v.eq.0) exit
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i4Msg6BitWords(i)=v - 1
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enddo
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msgsent=' '
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msgsent(1:12)=msg(1:12)
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! call packmsg(msg,i4Msg6BitWords,itype,bcontest) !Pack into 12 6-bit bytes
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! call unpackmsg(i4Msg6BitWords,msgsent,bcontest,mygrid) !Unpack to get msgsent
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write(cbits,1000) i4Msg6BitWords,32*i3bit
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1000 format(12b6.6,b8.8)
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read(cbits,1001) i1Msg8BitBytes(1:10)
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1001 format(10b8)
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i1Msg8BitBytes(10)=iand(i1Msg8BitBytes(10),transfer(128+64+32,0_1))
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i1Msg8BitBytes(11)=0
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icrc12=crc12(c_loc(i1Msg8BitBytes),11)
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icrc12=xor(icrc12, 42) ! TODO: jsherer - could change the crc here
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! For reference, here's how to check the CRC
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! i1Msg8BitBytes(10)=icrc12/256
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! i1Msg8BitBytes(11)=iand (icrc12,255)
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! checksumok = crc12_check(c_loc (i1Msg8BitBytes), 11)
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! if( checksumok ) write(*,*) 'Good checksum'
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write(cbits,1003) i4Msg6BitWords,i3bit,icrc12
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1003 format(12b6.6,b3.3,b12.12)
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read(cbits,1004) msgbits
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1004 format(87i1)
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call encode174(msgbits,codeword) !Encode the test message
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! Message structure: S7 D29 S7 D29 S7
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itone(1:7)=icos7a
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itone(36+1:36+7)=icos7b
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itone(NN-6:NN)=icos7c
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k=7
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do j=1,ND
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i=3*j -2
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k=k+1
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if(j.eq.30) k=k+7
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indx=codeword(i)*4 + codeword(i+1)*2 + codeword(i+2)
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itone(k)=indx
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enddo
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return
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end subroutine genjs8
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