[amsat-bb] Re: DTMF on HF?

Gus gus at 8p6sm.net
Fri Jan 10 19:19:39 PST 2014

Unfortunately, in some cases the differences are very close.  "C" and 
"3" have pairs with a differential only 1 Hz apart.

Perhaps some heuristic approach which examines several consecutive 
tone-pairs, looking for a single offset that would make them all valid?

On 01/10/2014 06:31 PM, Joe Leikhim wrote:
> Since DTMF has two tones for each number, it would seem possible that
> you could have some DSP detect the difference frequency of each pair and
> then either adjust its decoders or QSY the receiver's VCO to get a lock.
> There are a ton of small development boards like Raspberry PI that have
> hardware that might be able to do this.
> Has anybody got the AMSAT-bb daily digest to work through their e-mail
> provider other than Gmail?

Gus 8P6SM
The Easternmost Isle

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