Digital-to-Analog Converter (DAC)

A digital-to-analog converter (DAC or D-to-A) is a device that converts a digital (usually binary) code to an analog signal (current, voltage, or electric charge). An analog-to-digital converter (ADC) performs the reverse operation .

Basic ideal operationThe DAC fundamentally converts finite-precision numbers (usually fixed-point binary numbers) into a continuously varying physical quantity, usually an analogue electrical voltage.

In an ideal DAC, the numbers are output as a sequence of impulses, that are then filtered by a reconstruction filter. This would, in principle, reproduce a sampled signal precisely up to the Nyquist frequency, although a perfect reconstruction filter cannot be practically constructed as it has infinite phase delay; and there are errors due to quantisation .

DAC Characteristics:

1. Resolution2. Offset Error3. Gain Error4. Monotonicity5. Relative Accuracy

DACs are used in many other applications, such as voice synthesizers, automatic test system, and process control actuator. In addition, they allow computers to communicate with the real (analog) world.

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VoltageSwitch

ResistiveSummingNetwork

Amplifier

Input BinaryNumber

Analog VoltageOutput