In many applications, what you need is just extracting one frequency from a signal (that is, to know its amplitude). I was dreaming about an IC that allows selecting a frequency of interest, perhaps also, some passing band, and to output the amplitude of the frequency component, exactly like an LM317 allows selecting a regulation voltage. Of course, such IC would be limited in their range of frequencies. Applications include: audio, radio frequency selection, television, frequency response analyser, and even simply eliminating noise from a signal, without having to design a cumbersome sharp filter. Taking this question one step away, I ask about technologies/IC that allows frequency selection in some range of frequencies. The answer may focus on:
- bandpass filter technologies/IC that allows frequency selection
- possible "heterodyning" IC
To avoid too broad questioning, let me restrict the frequency range to 0-100MHz. Also, I need only general guidelines and keywords.