Before revision: Any analog signal (such as an FM radio transmission, a light wave or a sound) can be digitized using a very basic analog-to-digital converter , and the smallest and most energy efficient of these would be in the form of mixed-signal ICs.
After revision: Any analog signal (such as an FM radio transmission, a light wave or a sound) can be digitized using a very basic ADC , and the smallest and most energy efficient of these would be in the form of mixed-signal ICs.