Hello everyone,
I am a beginner in radio frequency. I have a question about sub1ghz. I have a copy of a remote controller with multiple frequencies. I took it apart and found that the silk screen of the main control was polished, and there was also a polished radio frequency chip. But I guessed from its crystal oscillator and packaging that it is a sub1ghz chip from China, codenamed cmt2300a (my guess). My question is, how does it receive the transmission signal in the case of unknown frequency? Can't the sub chip only receive one frequency at the same time? How is it done?