Go Down

Topic: Decoding CTCSS - Possible? (Read 1 time) previous topic - next topic

swoshie

Hello,

I am currently building a repeater logic for a radio project and I have the need to decode CTCSS as an access method.

I've searched quite a lot and found no one doing it with the Arduino, only PIC and I don't know if that's an accurate reading or not. There is still hardware decoders out there but they are old and costs a lot, all the new radios today have all the options in one big IC.  :P

My first thought was to use the pulseIn() function and measure the input line via a low pass filter and a schmitt trigger but have not yet tested this theory. Do you think it's possible? Can the readings be accurate enough to not open on a nearby CTCSS frequency?

Maybe someone has a better idea? All answers are welcome!

Best regards,
Swoshie

Magician

Quite possible, there is 48 notes recognition, which is pretty close:
http://coolarduino.wordpress.com/2011/09/03/arduino-musical-note-recognition-pushing-the-limits/
Better instead of UNO use Mega, more memory  'd not hurt. As messages "overlapped" with regular audio traffic (wiki says),  good quality LPF necessary, sharp 3-5 -th order, not ready to say if arduino could manage it or hardware / co-processor has to be

el_supremo

I doubt that it can be done with an Arduino. In some cases the tones are only about 3Hz apart which would make it very difficult to distinguish them.

Pete

BulletMagnet83

Maybe try a Teensy 3.0? Give yourself a bit of extra processing power :)

el_supremo


Go Up