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git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@8212 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
60 lines
2.4 KiB
Fortran
60 lines
2.4 KiB
Fortran
program jt65osdtest
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!
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! Demonstrate some procedures that can be used to implement an ordered-
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! statistics decoder for JT65.
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! 1. Test JT65 generator-matrix-based encoding by comparing codewords with
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! those produced by the tried-and-true KA9Q encoder
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! 2. Demonstrate how to reconfigure the generator matrix to make an arbitrary
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! subset of 12 symbols the systematic symbols, and show that re-encoding using
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! the subset of symbols regenerates the original codeword.
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!
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use jt65_generator_matrix
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use gf64math
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use packjt
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character*22 message
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integer m(12),cwka9q(63),cwk9an(63),cwtest(63)
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integer gmrb(12,63)
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data m/61,51,10,42,51,55, 3,29,53,55,58,42/ !"K9AN K1JT -25"
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message="K1ABC W9XYZ EN37"
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call packmsg(message,m,itype,.false.)
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write(*,*) 'Message text: ',message
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write(*,*) 'Message symbols:'
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write(*,'(12i3)') m
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! Encode using Karn encoder.
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call rs_encode(m,cwka9q)
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write(*,*) 'KA9Q codeword'
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write(*,'(63i3)') cwka9q
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! Encode using generator matrix.
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call gf64_encode(g,m,cwk9an)
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write(*,*) 'K9AN codeword'
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write(*,'(63i3)') cwk9an
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! The message symbols are the last 12 symbols of the codeword. For this test,
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! "pretend" that the symbols at positions 1,3,5,7,9,11,13,15,17,19,21,23 are
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! the best received symbols, i.e. the best symbols are all parity symbols.
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! Reorder columns of the generator matrix so that the best symbols are in front
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! and then use Gauss-Jordan elimination to create a generator matrix that
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! can be used to re-encode the best 12 symbols, producing the same codeword
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! that we started with.
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gmrb=g
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do i=1,12
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gmrb(1:12,i)=g(1:12,2*i-1)
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gmrb(1:12,i+12)=g(1:12,2*i)
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enddo
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call gf64_standardize_genmat(gmrb)
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! Now demonstrate that we can use the revised generator matrix to encode the 12
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! best symbols and recover the codeword that we started with.
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m(1:12)=cwk9an(1:23:2) !Take symbols 1,3,5,...23 as the message
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call gf64_encode(gmrb,m,cwtest) !reencode using the revised generator matrix
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write(*,*) 'Re-encode using generator matrix reconfigured to use odd-index symbols starting at 1 as the message:'
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write(*,'(12i3)') m
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write(*,*) 'Re-encoded codeword should be the same as the original codeword:'
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write(*,'(63i3)') cwtest !This should be the same as the original cw.
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end program jt65osdtest
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