At the transmitter end, i have inputs with tone generators attached to it to generate modulating signals with different freq to modulate with the carrier frequency. When the input is pressed, the relevant freq will be generated for transmission.

Just wondering at the receiver end, is it possible that i :

1) feed the signal directly into the PIC ( meaning can the PIC be programmed to recognise different frequencies? )

2) or do i use a decoder to decode the signal based on its frequency and feed the outputs parallelly into the PIC's I/O ports. So if the PIC detect a signal from one of the I/O ports, it will act accordingly.

3) oh yeah, if the answer is 2, i will be more than welcomed if anybody can suggest some good decoder ICs. Was thinking about using HT12D (Holtek) or LM567.

 

go with 2, and i suggest the LM567. decoding frequencies is way too tedious for a PIC; even if it worked it wouldn't be able to accomplish anything else while it was decoding. that's just not what pics are made for.

 

Thanks for the swift reply.

 

I'm presuming this is for remote control?, using tone generators is an extremely old, crude technique (early 1970's). Since then digital coding has been used (like the Holtek chips), which is far more reliable, and gives many more possibilities.

You can use PIC's to encode and decode the signals (check my IR tutorial), but the ready programmed Holtek devices are extremely cheap anyway.

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