66 lines
2.3 KiB
Plaintext
66 lines
2.3 KiB
Plaintext
subroutine gen9(msg0,ichk,msgsent,i4tone,itype)
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! Encodes a JT9 message and returns msgsent, the message as it will
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! be decoded, and an integer array i4tone(85) of 9-FSK tone values
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! in the range 0-8.
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use packjt
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character*22 msg0
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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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integer*4 i4Msg6BitWords(13) !72-bit message as 6-bit words
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integer*1 i1Msg8BitBytes(13) !72 bits and zero tail as 8-bit bytes
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integer*1 i1EncodedBits(207) !Encoded information-carrying bits
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integer*1 i1ScrambledBits(207) !Encoded bits after interleaving
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integer*4 i4DataSymbols(69) !Data symbols (values 0-7)
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integer*4 i4GrayCodedSymbols(69) !Gray-coded symbols (values 0-7)
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integer*4 i4tone(85) !Tone #s, data and sync (values 0-8)
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include 'jt9sync.f90'
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save
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if(msg0(1:1).eq.'@') then
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read(msg0(2:5),*,end=1,err=1) nfreq
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go to 2
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1 nfreq=1000
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2 i4tone(1)=nfreq
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else
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message=msg0
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do i=1,22
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if(ichar(message(i:i)).eq.0) then
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message(i:)=' '
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exit
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endif
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enddo
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do i=1,22 !Strip leading blanks
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if(message(1:1).ne.' ') exit
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message=message(i+1:)
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enddo
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call packmsg(message,i4Msg6BitWords,itype,.false.) !Pack into 12 6-bit bytes
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call unpackmsg(i4Msg6BitWords,msgsent,.false.,' ') !Unpack to get msgsent
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if(ichk.ne.0) go to 999
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call entail(i4Msg6BitWords,i1Msg8BitBytes) !Add tail, make 8-bit bytes
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nsym2=206
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call encode232(i1Msg8BitBytes,nsym2,i1EncodedBits) !Encode K=32, r=1/2
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i1EncodedBits(207)=0
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call interleave9(i1EncodedBits,1,i1ScrambledBits) !Interleave bits
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i1ScrambledBits(207)=0
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call packbits(i1ScrambledBits,69,3,i4DataSymbols) !Pk 3-bits into words
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call graycode(i4DataSymbols,69,1,i4GrayCodedSymbols) !Apply Gray code
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! Insert sync symbols at 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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i4tone(i)=0
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else
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j=j+1
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i4tone(i)=i4GrayCodedSymbols(j)+1
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endif
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enddo
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endif
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999 return
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end subroutine gen9
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