Analog to Digital Converter

An analog-to-digital converter is abbreviated ADC, A/D, or A to D. The device allows you to convert continuous signals to discrete digital numbers, which essentially results in a conversion from analog to digital. Usually an ADC is a device that converts and inputs analog voltage, or a current to a digital number to the magnitude of the voltage or current.

With changes arising daily in the universal devices, such as TV and its associated peripherals, the term analog to digital is popping up everywhere, but what are they used for, and why? In basic terms an analog to digital converter is a device that is capable of converting an analog signal to a digital format for additional storage, presentation and processing. A reverse of this procedure can be completed by a digital to analog conversion often used in computer sound cards or even radio systems.

There are seven common analog to digital converter structures which are commonly used:

  • Direct conversion
  • Successive-approximation
  • Ramp-compare
  • Delta-encoded
  • Pipeline
  • Sigma-Delta
  • Time-stretch

The classification is usually based upon the type of signals used in the systems. Before looking into the differences, let’s look into the terms that analog and digital mean. An analog signal is one in which the values taken can be continuous, for an example if a signal varies in magnitude between 0 volts and 5 volts, it can become any value between 0 and 5.

With a digital signal, there can only be one discrete value. For example, a signal ranging from zero to five volts could take values of 1, 2, 3, 4 and five in a digital system, however if a signal in the above digital system has the value of 2.2, at any one time it is represented by the nearest discrete value, which would be two in this case.

As a very special case, if there is a signal in a digital system and it is represented by only two values, being zero and one it is called a binary system which all computers are made up of, “binary” coding. This is a representation used by all current modern day communications, another good name for “binary” coding is the numbers 01010101010101010, which are what builds up the computer and telephone and thousands of other communication systems.

The use of analog systems have been swirling as implementing digital systems have become more cost effective over the last few years. Both systems, like any, have their own advantages and disadvantages. Analog systems allow the user to make use of more efficient bandwidth and are relatively immune to the noise. They are also less flexible to changes within the design. Analog systems are implemented within hardware components and are usually not flexible to change in their own parameters of input signals. Any change that is additionally done in an input parameter may require a fresh circuit design and implementation; this is where it can begin becoming costly, which you really don’t want to occur unless you love spending money.

Digital systems however, are greatly affected by any noise. The advantage with digital systems is there built using programmable components and a standardized circuit can handle digital signals and a system can be implemented throughout the software, this allows the components to be reused just by modifying the current program.

Most modern communication systems are digital systems – any analog inputs are converted to digital by a process called sampling and conversion from digital back to analog is by reconstruction.

You’ll find analog signals in very few pieces of modern technology, and of those that do use them, they are often highly specific niches, audiophiles being one of them.

This Analog to Digital Converter Review is Written/Updated on May 26th, 2010 and filed under Consumer Electronics. Both comments and pings are currently closed.

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