Not sure if this is the correct place for this question. It's a comms question though so hopefully relevant.
I have a question that goes as follows:
Question:
When generating a (7,3) cyclic block cyclic using the Generator polynomial G(X) = 1 + x^2 + x^3 + x^4
(i) Derive a table of valid codewords(ii) Draw the block diagram of a suitable linear shift register decoding circuit for the above code and indicate how the circuit would function
...
(iv) If the codeword 1 + x + x^5 + x^5 is received, what codeword was sent.
Problem:
My problem is the fact that this is a (7,3) code rather than a (7,4) code. I know how to work with (7,4) codes and I'm comfortable with generating the checksums. However, I'm not sure what changes as a result of the extra check bit. I fear either my circuit (below - answer to part ii) or my table of codewords is wrong (also below - answer to part i). This isn't helped by the fact that I can't match any of the codes to the one given in part (iii)
(Input at left)
ATTACHED
I have a question that goes as follows:
Question:
When generating a (7,3) cyclic block cyclic using the Generator polynomial G(X) = 1 + x^2 + x^3 + x^4
(i) Derive a table of valid codewords(ii) Draw the block diagram of a suitable linear shift register decoding circuit for the above code and indicate how the circuit would function
...
(iv) If the codeword 1 + x + x^5 + x^5 is received, what codeword was sent.
Problem:
My problem is the fact that this is a (7,3) code rather than a (7,4) code. I know how to work with (7,4) codes and I'm comfortable with generating the checksums. However, I'm not sure what changes as a result of the extra check bit. I fear either my circuit (below - answer to part ii) or my table of codewords is wrong (also below - answer to part i). This isn't helped by the fact that I can't match any of the codes to the one given in part (iii)
Rich (BB code):
The table:
Datablock Code Polynomials Code Values
========= ================ ===========
000 (0) * g(x) 0000000
001 (1) * g(x) 0011101
010 (x) * g(x) 0111010
011 (1+x) * g(x) 1010111
100 (x2) * g(x) 1110100
101 (1+x2) * g(x) 10010001
110 (x+x2) * g(x) 10101110
111 (1+x+x2) * g(x) 11001011
The circuit:ATTACHED
Attachments
Last edited by a moderator:
