To determine the carrier frequency if you don't know it you either:-
- Measure it with a capture (Not Lintronic) program which provides this data
- Look it up based on the known protocol. For example RC5 protocol is always 36 Khz, NEC protocol is always 38 Khz and Sony protocol is always 40 Khz
- If you have the data in Pronto captured format you can calculate it by taking the second HEX word in the command string (example 67) change to decimal (example 103) and you get (Example -- Frequency = 1000000 / (103* 0.241246) = 40,244 ) or 40 Khz
- Measure it with an oscilloscope or data logger
Common Cariier Frequencies are:-
- Philips RC5 is 36 Khz
- Philips RC6 is 36 Khz
- Philips RC-MM is 36Khz -- Used for multi media products
- Philips RECS is 38 Khz
- RCA protocol is 56 Khz
- Sony 12, 15 and 20 bit protocols use 40 Khz
- Sharp protocol uses 38 Khz
- Nokia protocol uses 38 Khz
- JVC uses 38 Khz
As you can see most companies use 38 Khz, so if you do not have capture facilities which can provide the carrier frequency, then try 38 Khz first because more often than not it will be 38 KHz you are using.