What are the characteristics of nominal FM output range and noise range ? There should be a reference point for classification. A filter -might- also help but it will highly depend on the noise characteristics since it will perform a frequency based classification. On Sun, Jun 24, 2012 at 9:57 PM, Manu Abraham wrot= e: > Hi, > > Maybe a filter could help ? > > Regards, > Manu > > On Sun, Jun 24, 2012 at 10:50 PM, wrote: > >> >> >> =A0 =A0 Hi, >> >> =A0 =A0 I want to build a FM radio squelch using a microprocessor with a= n ADC. >> =A0 =A0 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). >> >> =A0 =A0 What is the best way of doing this in software? >> >> =A0 =A0 Thanks for any idea. >> =A0 =A0 Mark Jordan >> >> >> >> >> >> -- >> http://www.piclist.com PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .