AVR-Chat

Motorola 2Way radios used this for years. It was called "noise squelch" or something like that. You have a high pass filter that cuts off above the top of the voice spectrum. Amplify and rectify the filter output. You will have a rectified output only when there is nothing to hear on the channel.

Jim
On Jun 24, 2012, at 10:19 AM, enkitec@gmail.com wrote:

> Hi,
> 
> I want to build a FM radio squelch using an ATMEGA8.
> The ADC will be sampling the FM radio audio output and turn on a 
> LED when there is only noise present. The LED will be off when someone 
> is using the channel (no noise, just voice).
> 
> What is the best way of doing this in software?
> 
> Thanks for any idea.
> Mark Jordan
> 
> 



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