Page "Analog signal" Paragraph 3

An analog signal has a theoretically infinite resolution.

In practice an analog signal is subject to electronic noise and distortion introduced by communication channels and signal processing operations, which can progressively degrade the signal-to-noise ratio.

In contrast, digital signals have a finite resolution.

Converting an analog signal to digital form introduces a constant low-level noise called quantization noise into the signal which determines the noise floor, but once in digital form the signal can in general be processed or transmitted without introducing additional noise or distortion.

Therefore as analog signal processing systems become more complex, they may ultimately degrade signal resolution to such an extent that their performance is surpassed by digital systems.

This explains the widespread use of digital signals in preference to analog in modern technology.

However a comparable performing digital system is more complex and can require more bandwidth than its analog counterpart.

In analog systems, it is difficult to detect when such degradation occurs.

However, in digital systems, degradation can not only be detected but corrected as well.