Basic definition – What is a digital-to-analog converter (DAC)? Choose the option that correctly describes the role of a DAC in everyday systems such as audio playback.
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AIt takes the digital information from an audio CD and converts it to a usable form.
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BIt allows the use of cheaper analog techniques, which are always simpler.
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CIt stores digital data on a hard drive.
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DIt converts direct current to alternating current.
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EIt measures analog signals and outputs digital codes.
Answer
Correct Answer: It takes the digital information from an audio CD and converts it to a usable form.
Explanation
Introduction / Context:Digital systems represent information as numbers. To drive real-world devices such as speakers, motors, or displays, we often need an analog signal. A digital-to-analog converter (DAC) performs precisely this function.
Given Data / Assumptions:
- Audio CDs, media players, and computers store audio as digital samples.
- Speakers require an analog voltage or current waveform.
- The question seeks a correct everyday description.
Concept / Approach:A DAC accepts a digital code and outputs an analog level proportional to that code. In audio, rapid updates of the DAC reconstruct a time-varying waveform which is then filtered and amplified to drive speakers. The principle applies to many domains, including control systems and instrumentation.
Step-by-Step Solution:Digital word → DAC input.DAC outputs an analog level corresponding to the code and reference.Reconstruction filter removes sampling images, yielding smooth audio.Amplifier drives the load with the recovered analog waveform.
Verification / Alternative check:Block diagrams of CD/DVD/streaming players show: storage/decoder → digital filter → DAC → analog filter → amplifier → speaker.
Why Other Options Are Wrong:Option B is misleading; DACs do not exist to “always” make things simpler.
Option C describes storage, not conversion.
Option D is a function of inverters or power electronics, not a DAC.
Option E describes an ADC (the opposite direction).
Common Pitfalls:Confusing sample rate with audio frequency content; reconstruction filtering is essential to avoid aliasing images in the output.
Final Answer:It takes the digital information from an audio CD and converts it to a usable form.