Digital vs analog: advantages and disadvantages

A digital signal has only discrete levels (0 and 1), while an analog signal varies continuously. Using digital signals has these advantages and disadvantages.

Advantages

1. High noise immunity: only HIGH and LOW must be recognised, so small noise does not corrupt the data.
2. Better accuracy: precision can be raised by adding more bits.
3. Easy storage: data can be kept in memories (RAM, ROM, flash) for long periods without loss.
4. Programmable: behaviour can be changed by software, e.g. microprocessors.
5. Easy design and testing using Boolean algebra; exact voltage values do not matter.
6. High integration: many gates fit on one IC, giving small size, low cost and high reliability.
7. Error detection and correction, encryption and compression are easy.
8. Copies are exact, and signals can be regenerated during long-distance transmission.

Disadvantages

1. Real world is analog: temperature, sound, pressure, etc. are analog, so ADCs and DACs are needed, which add cost, delay and complexity.
2. Quantisation error: converting to digital loses some information.
3. More bandwidth: a digital signal needs more bandwidth than the analog signal it carries.
4. Processing time: conversion and processing take time, which can limit very high-frequency work.
5. Power and synchronisation: fast digital circuits need clocks and timing control, and can use more power.