Any idea how make a program for propeller Syllabic Squelch

lcyepiz

Any·idea how detect the voice·(syllabic)·squelch.

Most comercial·radios/scanner for amateur ham, has a squelch control
but this a level control,·i searching info to do a voice switch that only
recognition voice, no the level.

I found http://www.ah6le.net/hf_squelch.html, has a circuit but no idea how this work
this circuit was orinally presented by Frank S. Reid (W9MKV) and David A. Link (W9YAN) in a August 1982 73 Magazine
but i cant get a copy of that article.


Any Idea, for detect voice with the propeller , only switch on·to syllabics words


thanks


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Juramento YAQUI.

Para ti no habrá sol, para ti no habrá muerte, para ti no habrá dolor, para ti no habrá calor, ni sed,· ni hambre, ni lluvia, ni aire, ni enfermedad, ni familia.Nada te causara temor, todo ha terminado para ti, excepto una cosa: HACER TU TRABAJO. En el puesto que has sido asignado, ahí te quedaras para la defensa de tu nación, de tu gente, de tu raza, de tus costumbres, de tu religión.! Juras cumplir con el divino mandato AHUI....!

Luis C. Yepiz
XE2NBW
·

VIRAND

Do you mean VOX (Voice Operated Transmit)?
Or some way of extracting received voice from static and code stations?
Or like closed captioning?

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I should be typing in Spin now.
Coming soon. My open Propeller Project Pages and favorite links index.

lcyepiz

The idea·is detect the audio from the receiver and hold in mute ·if received audio is static, tone , music etc,

If the audio received is human voice (syllabic) release the mute.



I found in internet a circuit from micor but no available· http://www.repeater-builder.com/rbtip/micorsquelch.html#Open%20Emitter

·and the next circuit:

the text from www.repeater-builder.com



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Juramento YAQUI.

Para ti no habrá sol, para ti no habrá muerte, para ti no habrá dolor, para ti no habrá calor, ni sed,· ni hambre, ni lluvia, ni aire, ni enfermedad, ni familia.Nada te causara temor, todo ha terminado para ti, excepto una cosa: HACER TU TRABAJO. En el puesto que has sido asignado, ahí te quedaras para la defensa de tu nación, de tu gente, de tu raza, de tus costumbres, de tu religión.! Juras cumplir con el divino mandato AHUI....!

Luis C. Yepiz
XE2NBW
·

Dave Hein

Luis,

There is some information on voice activity detection (VAD) in wikipedia.· Most of the energy in a voiced signal is in the lower frequencies.· You could try to make a simple detector that would compare the energy in the lower frequencies to the overall energy in the signal.· You could use a simple bandpass filter from something like 200 Hz to 1 KHz.· The algorithm would be something like the following:

1. Compute the total AC energy in the signal and compare against a minimum threshold

2. If the minimum threshold is exceeded then bandpass the signal and compute the energy in the band

3. Compute the ratio of the energy in the low frequency band and the overall energy

4. If the ratio is greater than a certain threshold, such as 80%, then the signal is considered voiced

You may need other tests to eliminate extraneous voice triggers and other types of RF noise, but I think this would work.

The wikipedia article references G.729, which has a very sophisticated voice detector in Annex B, but I think that is much more complex than you need.

Dave

Leon

When I worked on military radio systems at Racal someone mentioned neural net software that had been developed for a squelch system. This was probably what he saw:

ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel3%2F1166%2F7915%2F00337021.pdf%3Farnumber%3D337021&authDecision=-203

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Leon Heller
Amateur radio callsign: G1HSM