Explain the concept of ADC (Analog-to-Digital Converter) 

An Analog-to-Digital Converter (ADC) is a device that converts an analog signal, which varies continuously, into a digital signal, which represents discrete values. Key functions include:

1. **Sampling**: Measuring the analog signal at regular intervals.

2. **Quantization**: Mapping each sample to a discrete digital value.

3. **Encoding**: Converting the quantized values into a digital format for processing by digital systems.

ADCs are used in various applications, such as sensors, audio processing, and data acquisition, to enable digital systems to interact with analog signals.