Soundproofing, Optical Technologies, and Wave Applications

Vocabulary flashcards covering soundproofing, active noise control, public-address systems, optical devices, lasers, and wave application quick-memory items from the lecture notes.

Soundproofing

A practice that aims to reduce sound entering, leaving, or echoing within a space using porous panels and curtains to absorb sound energy.

Active noise control

A method that uses an opposite sound wave to create destructive interference and reduce steady unwanted noise such as an engine hum.

Public-address signal path

The sequential signal flow in a public-address system: $\text{microphone} \rightarrow \text{electrical signal} \rightarrow \text{amplifier} \rightarrow \text{speaker} \rightarrow \text{sound wave}$.

Amplifier

A component that increases the strength of a weak electrical signal so the loudspeaker can produce clearer or stronger sound.

LED (Light-Emitting Diode)

A light source that converts more electrical energy into useful light and wastes less as heat than older lighting.

Li-Fi

A technology that transmits data through very rapid changes in light intensity that occur too fast for human eyes to notice.

Hologram / Holographic display

A device or image that uses light interference patterns to preserve depth information, allowing a three-dimensional image to be viewed from different positions.

Barcode laser scanner

A scanner that reads differences in reflected light from alternating dark and light bars and converts the reflected pattern into digital information.

Laser

A device that produces a focused, narrow, highly collimated beam that spreads very little, making it useful for scanning and distance measurement.

Total internal reflection

The optical principle that keeps guided light inside an optical fiber, allowing digital data to travel long distances through glass fibers.

Laser safety

Safety protocol stating to never point a laser at eyes, vehicles, or aircraft, as even a small laser can create a serious safety hazard.

Reflection

The wave phenomenon responsible for producing a mirror image.

Refraction

The wave phenomenon employed in eyeglasses to redirect light.

Diffraction

The wave phenomenon responsible for sound bending or spreading around a doorway.

Destructive interference

The physical wave phenomenon behind noise cancellation.

Doppler effect

The wave phenomenon where a moving target changes the observed frequency.

Sonar

A wave technology used for seafloor mapping.

Radar

A wave technology used for aircraft distance and obstacle detection.

Ultrasound

A wave technology used for medical imaging with reflected sound.