> Eric Jacobsen<eric.jacobsen@ieee.org> wrote:
>
>> On 8/4/2009 10:58 AM, gct wrote:
>
>>> Quick question I'm sure someone can put to bed easily: Is it possible to
>>> shorten BCH codes in the same way that you shorten Reed-Solomon? My
>>> instinct is yes, but I want to make sure it's not going to do anything evil
>>> like reduce the minimum distance...
>
>> Of course it's possible, and it's commonly done. It won't reduce the
>> minimum distance since shortening just reduces the set of codewords
>> used, it doesn't move or alter them.
>
> Actually, shortening a BCH code can increase (not reduce) the
> minimum distance. For a trivial example of this, shorten
> the code to contain a single information bit. But there
> are less trivial examples.
>
> Steve
Yup. If the minimum distance codewords are removed from the original
codeword set in the shortening process then the min. dist. in the
remaining set is, naturally, larger.
Sometimes it's worth carefully picking the shortening method for this
reason.
--
Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com
Reply by Steve Pope●August 4, 20092009-08-04
Eric Jacobsen <eric.jacobsen@ieee.org> wrote:
>On 8/4/2009 10:58 AM, gct wrote:
>> Quick question I'm sure someone can put to bed easily: Is it possible to
>> shorten BCH codes in the same way that you shorten Reed-Solomon? My
>> instinct is yes, but I want to make sure it's not going to do anything evil
>> like reduce the minimum distance...
>Of course it's possible, and it's commonly done. It won't reduce the
>minimum distance since shortening just reduces the set of codewords
>used, it doesn't move or alter them.
Actually, shortening a BCH code can increase (not reduce) the
minimum distance. For a trivial example of this, shorten
the code to contain a single information bit. But there
are less trivial examples.
Steve
Reply by Eric Jacobsen●August 4, 20092009-08-04
On 8/4/2009 10:58 AM, gct wrote:
> Quick question I'm sure someone can put to bed easily: Is it possible to
> shorten BCH codes in the same way that you shorten Reed-Solomon? My
> instinct is yes, but I want to make sure it's not going to do anything evil
> like reduce the minimum distance...
Of course it's possible, and it's commonly done. It won't reduce the
minimum distance since shortening just reduces the set of codewords
used, it doesn't move or alter them.
--
Eric Jacobsen
Minister of Algorithms
Abineau Communications
http://www.abineau.com
Reply by gct●August 4, 20092009-08-04
Quick question I'm sure someone can put to bed easily: Is it possible to
shorten BCH codes in the same way that you shorten Reed-Solomon? My
instinct is yes, but I want to make sure it's not going to do anything evil
like reduce the minimum distance...