What Is An Analogue Signal?

Date First Published: 11th June 2022

Topic: Computer Networking

Subtopic: Data Transmission Technologies

Article Type: Computer Terms & Definitions

Difficulty Level: 4/10

Learn more about what an analogue signal is in this article.

An analogue signal consists of a continuous range of values representing one quantity that is analogous to another quantity. For example, in an analogue audio signal, the signal voltage continuously varies depending on the sound wave pressure. Analogue allows information to be handled by the equipment that continuously changes, such as voltage and waves. Examples of analogue devices are VCR (video cassette recorder) players and tapes, traditional laser photocopiers, and CRT (cathode ray tube) monitors and televisions. A clock with hands is an example of an analogue device as the hands continuously move around the face and the clock can indicate all possible times of day.

Analogue signals are different to digital signals, where information is translated into a binary format (0s and 1s) before being stored on a digital device. Each bit represents two different amplitudes and most communications use digital signals. Unlike analogue signals, digital signals are non-continuous.

Analogue signals are suitable for audio and video transmissions due to their higher density to present more information, use less bandwidth than digital sounds, and protect the natural form of sound. However, digital signals are more compressible, easier to edit without modifying the original copy and easier to transfer over networks. In addition, they can be encrypted. Whilst analogue signals can be encrypted, they cannot be encrypted as effectively as digital signals.

Analogue to Digital Conversion

Computers can only read digital data. Analogue data can be converted to digital data by an analogue-to-digital converter. For example, DSL modems send and receive analogue signals to and from the outside and those signals are converted to digital signals and sent to a router or computer. It can also work in reverse. Digital data can be converted to analogue signal by using a digital-to-analogue converter. For example, a dial-up modem takes digital data and converts it to analogue signals that can be transmitted over telephone lines.

Advantages and Disadvantages Of Analogue Signals

• They are more suitable for audio and video transmission.
• They use less bandwidth than digital signals.
• They show changes in the physical phenomena more accurately, such as pressure, light, sound, or temperature, since they are continuous.
• In terms of electrical tolerance, they are less sensitive.

• They are more vulnerable to noise and distortion than digital signals.
• Analogue signals usually have a lower signal quality than digital signals.
• The analogue wires are quite expensive and not easily portable.
• Data transmission at long distances can lead to signal transmission issues.