Conversions analogique-numérique et numérique-analogique (partie 1)

Electronics has invaded all fields, both consumer and professional, thanks to its low cost and adaptability.

The functions it performs are realized almost exclusively with digital rather than analog electronics.

This choice is often justified by the well-known advantages of digital technology, such as high parameter stability, excellent reproducibility of results and enhanced functionality.

For most applications, there are now easy and very inexpensive solutions for digitizing.

This means we can benefit from the spectacular progress made in the digital field in terms of cost, possibilities and adaptability, and all this for ever lower power consumption. This enables the development of an ever-increasing number of applications, including portable ones.

The main elements of these functions are :

• An interface with the analog world: analog ® digital (A ® N) and digital ® analog (N ® A). In most cases, on a macroscopic scale, the external world is analog. Analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) are responsible for interfacing between the outside world and the hardware's digital core. ADCs and DACs are most often found as the building blocks of a data acquisition system and/or a digital-to-analog conversion system.

• The necessary processing and communication speeds are now available at a cost and power consumption that allow them to be used everywhere. Over the decade of the 1980s, the price and consumption per memory bit fell by a factor of around 100, and the decade of the 1990s saw a similar decline. Experts predict a similar trend for the decade 2000-2010.

• What's more, silicon integration and ever-smaller packages mean that entire boards can be replaced by a single circuit, which can then be integrated into any type of application.

• Communication is now almost entirely carried out via digital interfaces, making it possible to interconnect a whole range of devices at very low cost and with no loss of information.

  Note :

  This article on analog-to-digital and digital-to-analog conversion is divided into three parts:

  • [E 370] : Principles ;

  • : Technical description and architectures ;

  • : Market, technology and applications.