Analogue to Digital Converters

Analogue to digital converters (ADCs) are devices that convert analogue input signals into a digital output signal, for example a sound captured from a microphone or light entering a digital camera. These analogue inputs are then converted into a digital signal output as either sound from a speaker or a picture in a camera.

ADCs sample the input signals at specific points in time which reduces the allowable bandwidth of the input signal for increased efficiency.

What does an analogue to digital converter do?

Audio analogue to digital converters captures and converts analogue sounds into digital signals using a mathematical function called quantisation. This conversion occurs periodically instead of continuing to minimise noise generation.

Video analogue to digital to converters are a high-frequency low- to medium-resolution type that is used to convert analogue video data into digital video signals such as displays on digital cameras.

General Purpose ADCs are considered the base type of ADC un of the mill ADCs are used to convert analogue signals to digital signals in equipment such as temperature sensors.

Types of analogue to digital converters

The most widely used types of ADCs are:

• Flash - Flash ADCs are considered the fastest way to convert an analogue signal to a digital signal and are suitable for applications requiring very large bandwidths such as satellite communication, data acquisition, radar processing and sampling oscilloscopes.
• Successive approximation - A successive approximation ADC converts continuous analogue waveform into digital using a binary search through all quantization levels before finally combining a digital output for each conversion.
• Sigma-delta - Sigma delta ADCs converts the signal by large factors and filters the desired signal. They offer high resolution, low power consumption and are used in applications such as process control, temperature measurement and weight measurement scale devices.

Applications

Audio ADCs are widely used in applications such as:

• Professional audio mixing consoles
• Home theatre systems
• Musical instruments

Video ADCs are used in:

• Medical Imaging
• Digital Instrumentation
• Digital cameras

General Purpose ADCs are used primarily in applications such as:

• Battery Operated Systems
• Sensor Interfaces
• Frequency measurement