34 lines
800 B
Plaintext
34 lines
800 B
Plaintext
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subroutine encode232(dat,nsym,symbol)
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! Convolutional encoder for a K=32, r=1/2 code.
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integer*1 dat(13) !User data, packed 8 bits per byte
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integer*1 symbol(206) !Channel symbols, one bit per byte
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integer*1 i1
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include 'conv232.f90'
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nstate=0
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k=0
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do j=1,nsym
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do i=7,0,-1
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i1=dat(j)
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i4=i1
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if (i4.lt.0) i4=i4+256
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nstate=ior(ishft(nstate,1),iand(ishft(i4,-i),1))
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n=iand(nstate,npoly1)
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n=ieor(n,ishft(n,-16))
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k=k+1
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symbol(k)=partab(iand(ieor(n,ishft(n,-8)),255))
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n=iand(nstate,npoly2)
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n=ieor(n,ishft(n,-16))
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k=k+1
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symbol(k)=partab(iand(ieor(n,ishft(n,-8)),255))
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if(k.ge.nsym) go to 100
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enddo
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enddo
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100 continue
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return
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end subroutine encode232
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