Nature of real-world inputs: “Most signals applied to a computer for storage or processing are inherently digital.” Evaluate this statement considering sensors and user inputs.
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ACorrect
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BIncorrect
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COnly true for network packets
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DOnly true for keyboard input
Answer
Correct Answer: Incorrect
Explanation
Introduction / Context:Computers ultimately process digital data, but many sources in the physical world are analog: temperature, pressure, sound, light intensity, and motion. Understanding this distinction is essential for mixed-signal system design.
Given Data / Assumptions:
- Sensors often produce analog voltages or currents proportional to a physical quantity.
- Human interfaces like microphones and touch sensors produce analog signals before digitization.
- Digital inputs (keyboards, network packets) also exist but are not the majority of raw physical phenomena.
Concept / Approach:Analog front ends (AFEs) condition sensor outputs, which are then digitized by ADCs. Once converted, computers handle storage/processing. While some inputs are natively digital (e.g., USB keyboard, Ethernet), the broader universe of real-world inputs is analog until converted.
Step-by-Step Solution:
List typical inputs: audio, temperature, position → analog.Show conversion path: sensor → amplifier/filter → ADC → digital data.Contrast with natively digital sources (files, packets) which are already coded.Therefore the general statement “most inputs are digital” is incorrect.Verification / Alternative check:System block diagrams for data acquisition, IoT nodes, and embedded controllers consistently show pervasive ADC stages for physical-world sensing.
Why Other Options Are Wrong:Correct: Ignores the prevalence of analog sensors.
“Only true for network packets/keyboard” narrows scope to special cases rather than the general reality of interfacing with the physical world.
Common Pitfalls:Equating “processed by a computer” with “originated as digital.” Many signals are digitized only after acquisition.
Final Answer:Incorrect