Module 05: Waves and Optics · quiz worth 21 pts
This prevents the common mistake that digital means a special kind of wave.
The information: sound, text, image, or measurements.
A physical quantity varied to represent the message.
The path: wire, fiber, or space. Analog and digital data can use any of them.
Optional NASA reference: The Electromagnetic Spectrum compares radio, microwave, infrared, visible, and higher-frequency bands. It is a band overview, not a complete telecommunications or encoding lesson.
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Analog representation varies continuously. Digital representation uses discrete allowed values, often bits 0 and 1. Either can travel as voltage or current in wire, light in fiber, or electromagnetic radiation through space. Digital does not mean wired pulse, and analog does not mean radio; those are possible carriers.
Define the data first, then name how it travels.
Continuous values are analog; discrete allowed symbols are digital.
Voltage, light, or radio can carry either representation after encoding or modulation.
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Convert sound, images, or text into a signal representation.
Place information on a carrier suited to wire, fiber, or space.
The signal weakens and can collect noise or overlap other transmissions.
Select the intended signal and reconstruct the information.
Digital systems can regenerate symbols and use redundant bits to detect or correct some errors.
Analog preserves continuous variation directly, but accumulated noise is difficult to separate from intended variation. Digital thresholds allow regeneration, so small noise can be rejected. Digital still has finite sampling, quantization, bandwidth, synchronization, storage, energy, and error limits. Severe noise can cross a threshold and change a bit.
Wireless users share limited spectrum. Overlap in frequency, time, and reception area can interfere, so systems divide users by frequency bands, time, code, direction, or location. Higher carrier frequency may support wider bandwidth, but range also depends on power, antennas, absorption, obstacles, noise, and regulation. Directional antennas improve selection but do not prevent all interference.
A parabolic reflector gathers weak radio waves and focuses them toward a receiver. Electronics amplify and digitize the signal; computers analyze it into data products and images. Radio telescopes can work through clouds and during daytime but remain vulnerable to human-made radio interference.
A photon is a discrete packet of electromagnetic energy. In a photovoltaic cell, absorbed photons create mobile charge carriers in a semiconductor. An internal electric field separates them so a circuit can deliver current. Light sensors, photocopiers, and smoke detectors use related light-to-electrical-response ideas.
Use continuous or discrete evidence, not the carrier's name.
Identify the physical signal and where it travels.
Connect a benefit or limit to thresholds, noise, bandwidth, interference, focusing, or photon absorption.
Follow input, conversion, transmission or interaction, receiver, and output.
Answer every 05.08B question, review the rubric, and upload it to the matching Canvas item.
Choose the physical mechanism, not merely the newest-sounding technology.
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