Physics – 3.3 Electromagnetic spectrum | e-Consult

The process of converting an analogue voltage signal into a digital signal is called analogue-to-digital conversion (ADC). This typically involves the following steps:

1. Sampling: The analogue voltage is measured at regular intervals (sampled).
2. Quantisation: The amplitude of the sampled voltage is compared to a series of discrete voltage levels. Each voltage level is assigned a unique binary code.
3. Encoding: The binary code representing the amplitude is output as a digital signal.

The number of bits used to represent the digital signal is known as the resolution of the ADC. The more bits used, the more discrete voltage levels are available, and the more accurately the analogue signal can be represented digitally. A higher resolution leads to greater accuracy in the conversion, reducing the quantization error (the difference between the actual analogue value and its digital representation). For example, a 1-bit ADC can only represent two levels (0 or 1), while a 10-bit ADC can represent 2¹⁰ = 1024 levels. Therefore, a higher number of bits results in a more precise digital representation of the original analogue signal.