11 Jun
2012
11 Jun
'12
10:02 p.m.
On 11 Jun 2012 at 20:21, Tony Duell wrote:
Doesn;t that assume the 'extra' bits are known
to be correct. Those
can be in error too (even if the'real' data bits are correct),
Not necessarily--they're included in the Hamming distance, so a
single error, even in the syndrome bits can be corrected.
A 21 bit word for a 16 bit word will detect all single-bit errors but
a pure Hamming SECDED would require 22 bits (4 SEC + 1 added parity).
However, there exist other codes with SECDED properties--Hsiao codes-
-that will allow for SECDED in (21:16). I believe that the popular
(72:64) SECDED code is a shortened Hamming code.
--Chuck