[amsat-bb] Fwd: Re: Re: DTMF on HF?

[Joe Leikhim]

True,
But fixing on the receive end would be more spectrum efficient. And you
need to autotune the suppressed carrier anyway requiring receiver side
complexity, so why not give DSP a challenge to do it in the blind?

With DSP so readily available, I am surprised doppler correction of
voice has not been explored.


On 1/11/2014 12:05 AM, kc6uqh at cox.net wrote:
> Joe,
>   A -16dB pilot carrier would solve the frequency offset problem. This was a
> common solution for Marine shore stations in the last century.
> Art,
> KC6UQH
>
> -----Original Message-----
> From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> Behalf Of Joe Leikhim
> Sent: Friday, January 10, 2014 2:31 PM
> To: amsat-bb at AMSAT.Org
> Subject: [amsat-bb] Re: DTMF on HF?
>
> 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?
>
> --
> Joe Leikhim
>
>
> Leikhim and Associates
>
> Communications Consultants
>
> Oviedo, Florida
>
> JLeikhim at Leikhim.com
>
> 407-982-0446
>
> WWW.LEIKHIM.COM
>
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-- 
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

JLeikhim at Leikhim.com

407-982-0446

WWW.LEIKHIM.COM