Analog-to-digital converter

4-channel stereo multiplexed analog-to-digital converter WM8775SEDS made by Wolfson Microelectronics placed on a X-Fi Fatal1ty Pro sound card.

An analog-to-digital converter (abbreviated ADC, A/D or A to D) is an electronic integrated circuit that converts a continuous quantity to a discrete time digital number. An ADC may also provide an isolated measurement. The reverse operation is performed by a digital-to-analog converter (DAC).

Typically, an ADC is an electronic device that converts an input analog voltage or current to a digital number. The size of the number grows with an increase in the input voltage or current. However, some non-electronic or only partially electronic devices, such as rotary encoders, can also be considered ADCs.

Analog-to-digital Converter Media

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  AD570 8-bit successive-approximation analog-to-digital converter

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  Analog Devices designed the first monolithic ADC, the 10-bit AD571, in 1978. The AD570 is a selected version of the AD571 10-bit A-to-D converter.

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  INTERSIL ICL7107. 3.5 digit (i.e. conversion from analog to a numeric range of 0 to 1999 vs. 3 digit range of 0 to 999, typically used in meters, counters, etc.) single-chip A/D converter

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  INTERSIL ICL7107. 31/2 Digit Single Chip A/D Converter The ICL7107 is a high performance, low power, 3.5 digit analog to digital converter. The IC includes internal circuitry for seven segment decoders, display drivers, reference voltage source and a clock.

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  Comparison of quantizing a sinusoid to 64 levels (6 bits) and 256 levels (8 bits). The additive noise created by 6-bit quantization is 12 dB greater than the noise created by 8-bit quantization. When the spectral distribution is flat, as in this example, the 12 dB difference manifests as a measurable difference in the noise floors.

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  Analog to digital conversion as shown with fig. 1 and fig. 2

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  General symbol for an Analog to Digital Converter (ADC)

References

• Allen, Phillip E.. CMOS Analog Circuit Design. ISBN 0-19-511644-5.
• The Data Conversion Handbook (2005)Elsevier: Newnes. ISBN 0-7506-7841-0. Retrieved 2011-08-01.
• Johns, David. Analog Integrated Circuit Design (1997)Wiley. ISBN 0-471-14448-7.
• Knoll, Glenn F.. Radiation Detection and Measurement (1989). New York: John Wiley & Sons. p. 665–666.
• Liu, Mingliang. Demystifying Switched-Capacitor Circuits (2006)Newnes. ISBN 0-7506-7907-7.
• Nicholson, P. W.. Nuclear Electronics (1974). New York: John Wiley & Sons. p. 315–316.
• Norsworthy, Steven R.. Delta-Sigma Data Converters (1997)IEEE Press. ISBN 0-7803-1045-4.
• Razavi, Behzad. Principles of Data Conversion System Design (1995). New York, NY: IEEE Press. ISBN 0-7803-1093-4.
• Staller, Len. Understanding analog to digital converter specifications. Embedded Systems Design (February 24, 2005).
• Walden, R. H.. Analog-to-digital converter survey and analysis. IEEE Journal on Selected Areas in Communications 17 (4) (1999). p. 539–550. doi:10.1109/49.761034.

More websites

• Counting Type ADC Archived 2012-03-26 at the Wayback Machine A simple tutorial showing how to build your first ADC.
• An Introduction to Delta Sigma Converters A very nice overview of Delta-Sigma converter theory.
• Digital Dynamic Analysis of A/D Conversion Systems through Evaluation Software based on FFT/DFT Analysis RF Expo East, 1987
• Which ADC Architecture Is Right for Your Application? Archived 2013-02-10 at the Wayback Machine article by Walt Kester
• AN71 - The Care and Feeding of High Performance ADCs Real world circuit and layout advice
• ADC and DAC Glossary Archived 2009-11-24 at the Wayback Machine Defines commonly used technical terms.
• Signal processing and system aspects of time-interleaved ADCs. Archived 2011-08-21 at the Wayback Machine
• Introduction to ADC in AVR - Analog to digital conversion with Atmel microcontrollers