Hello Leigh and Jose,
>The parameters to look for from Patrick are the RS code groups and
>maximum correction coefficient. It is likely that the same seed data p
>is used in all cases, so there is no need for a registry of data codes.
>(I.e., if you can decode it, you don't need to know what it means since
>you have already found the right decoder g and frequency f).
I use a limited sub-set of the RS code groups because through translation in
time and in frequency RS codes are not orthogonal between themselves which is
logic as RS has a set of solutions which are cyclic by parts (I don't see this
in the litterature but it is obvious when you see the solutions...).
The problem is to stay with a fix relationship between each RS solution and its
mode label ("0" for "BPSK31"...), exactly as in SSTV each code sent previously
to the SSTV picture is related to a given SSTV code.
73
Patrick
----- Original Message -----
From: Leigh L Klotz, Jr.
To: digitalradio@yahoogroups.com
Sent: Friday, December 01, 2006 5:38 AM
Subject: Re: [digitalradio] USA: No Advanced Digital HF Data Comms
From what I can gather, the code is just an ECC'd data block and the
contents of the data aren't that important; it is the decodability
itself that is. If you can use arbitrary modem decoder g() and decode
data p with center frequency f with g(p,f) yielding null|(q,r) where r
is the correction coefficient, then you iterate over all decoders g and
pick the one that produces the highest r, without reference to q. In
all likelihood, only one decoder g() will yield a non-null result,
however, if you also iterate over frequencies f then you may get
multiple succesful decodes.
The parameters to look for from Patrick are the RS code groups and
maximum correction coefficient. It is likely that the same seed data p
is used in all cases, so there is no need for a registry of data codes.
(I.e., if you can decode it, you don't need to know what it means since
you have already found the right decoder g and frequency f).
73,
Leigh/WA5ZNU
On Thu, 30 Nov 2006 1:08 pm, Jose A. Amador wrote:
> I see it would be interesting to "register and publish" the codes that
> Patrick used by some "central authority"
> (maybe, Patrick himself). For me, it is similar to the I2C codes
> that the semiconductor industry
> uses, and Philips, as inventor of the concept, is the registering
> authority.
