ADC vs DAC-Difference between ADC and DAC

This page on ADC vs DAC describes difference between ADC and DAC.The other useful links to difference between various terms are provided here.


ADC-Analog to Digital Converter

ADC, Analog to Digital Converter

An electronic integrated circuit which transforms a signal from analog(continuous) form to digital(discrete) form is known as ADC.

Analog signals are directly measurable quantities while digital signals only have two states(binary 0 and binary 1). The heart of data acquision system is ADC. The digital systems require discrete digital data.

Purpose of Analog to Digital conversion:
• Processors perform arithmatic operations on digital signals.
• Signals in digital form are less susceptible to effects of noise.
• ADC provides link between analog world (of transducers) and digital world (of data and signal processing).

Following are the types of Analog to Digital Converter(ADC):
➨Counter type(simplest)
➨Successive Approximation
➨Flash ADC
➨Sigma Delta
Refer Difference between various types of ADC➤.

Applications:
1. Digital Voltmeter: measures voltage in analog and convert to digital form using ADC for digital representation form.
2. Mobile phone: Analog voice is converted to digital form for further processing(speech compression,encoding etc.) before it is converted back to analog form for transmission.
3. Scanner: When we take photo, the scanner uses ADC internally to convert analog information provided by picture into digital information.
4. Voice Recorder: It uses ADC to convert analog voice information to the digital information. Latest VOIP solutions utilize the same concept.

DAC-Digital to Analog Converter

DAC, Digital to Analog Converter

To convert digital values to analog voltage DAC is used. It performs inverse operation of analog to digital converter. The same has been depicted in the fig-2.

Analog output = ( Digital Input/(2N -1) )* Reference Input

There are two types of DACs:
• Weighted Resistor
• Resistive Divider
Refer Difference between various types of DAC➤.

Following specifications are considered for the design, development as well as selection of DAC(Digital to Analog Converter).
➨Resolution
➨Reference voltages
➨Settling Time
➨Linearity
➨Speed
➨Errors

Applications:
• Modems need DAC to convert data to analog form so that it can be carried over telephone wires.
• Video adapters also need DACs known as RAMDACs to convert digital form of data to analog form.
• Digital Motor Control
• Printers
• Sound Equipments
• Function Generators or Oscilloscopes
• Digital Audio

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