[amsat-bb] Fwd: Re: Re: DTMF on HF?
rhyolite at leikhim.com
Fri Jan 10 21:20:48 PST 2014
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:
> A -16dB pilot carrier would solve the frequency offset problem. This was a
> common solution for Marine shore stations in the last century.
> -----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
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Leikhim and Associates
JLeikhim at Leikhim.com
More information about the AMSAT-BB