Related Experiment Video
Updated: Dec 27, 2025
08:39
Shaping the Amplitude and Phase of Laser Beams by Using a Phase-only Spatial Light Modulator
Published on: January 28, 2019
10.3K
Carrierless amplitude and phase modulation in wireless visible light communication systems.
N Bamiedakis1, R V Penty1, I H White1
1Centre for Photonic Systems, Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK.
Summary
Carrierless amplitude and phase (CAP) modulation enhances visible light communication (VLC) systems by enabling higher data rates. This spectrally efficient scheme overcomes LED bandwidth limitations for improved optical wireless communication.
Area of Science:
- Optical Wireless Communication
- Data Transmission Technologies
Background:
- Visible Light Communications (VLCs) offer integrated illumination and data services using LEDs.
- LED bandwidth limitations restrict high-speed data transmission in VLC systems.
Purpose of the Study:
- To review Carrierless Amplitude and Phase (CAP) modulation for indoor VLC systems.
- To explore CAP modulation's potential for mitigating bandwidth limitations and increasing data rates.
Main Methods:
- Introduction to the fundamental characteristics of CAP modulation.
- Review of CAP modulation's application and performance in VLC contexts.
- Analysis of inherent attributes and limitations of CAP modulation.
Main Results:
- CAP modulation is a spectrally efficient scheme with significant practical implementation interest.
- Advances in CAP modulation aim to enhance performance for VLC applications.
- Experimental demonstrations showcase successful LED-based VLC links using CAP modulation.
Conclusions:
- CAP modulation presents a viable solution for achieving higher data rates in VLC systems.
- Further research and development are exploring CAP modulation's full potential in optical wireless communication.
Related Concept Videos
02:12The Wave Nature of Light
60.3K
The nature of light has been a subject of inquiry since antiquity. In the seventeenth century, Isaac Newton performed experiments with lenses and prisms and was able to demonstrate that white light consists of the individual colors of the rainbow combined together. Newton explained his optics findings in terms of a "corpuscular" view of light, in which light was composed of streams of extremely tiny particles traveling at high speeds according to Newton's laws of motion.
60.3K
01:07Propagation of Waves
2.8K
When a wave propagates from one medium to another, part of it may get reflected in the first medium, and part of it may get transmitted to the second medium. In such a case, the interface of the two mediums can be considered as a boundary that is neither fixed nor free.
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
Consider a scenario where a wave propagates from a string of low linear mass density to a string of high linear mass density. In such a case, the reflected wave is out of phase with respect to the incident wave, however the...
2.8K
01:30Propagation Speed of Electromagnetic Waves
4.5K
Electromagnetic waves are consistent with Ampere's law. Assuming there is no conduction current Ampere's law is given as:
4.5K
01:22Energy Carried By Electromagnetic Waves
3.7K
Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes, this energy is obvious, such as in the summer sun's warmth. At other times, it is subtle, such as the unfelt energy of gamma rays, which can destroy living cells. Electromagnetic waves bring energy into a system through their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. However, there is energy in an electromagnetic wave,...
3.7K
01:21Time and frequency -Domain Interpretation of Phase-lag Control
350
Phase-lag controllers are widely used in control systems to improve stability and reduce steady-state errors. A dimmer switch controlling the brightness of a light bulb serves as a practical example of phase-lag control, gradually adjusting the bulb's brightness. Mathematically, phase-lag control or low-pass filtering is represented when the factor 'a' is less than 1.
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any...
350
02:37The Electromagnetic Spectrum
64.1K
The electromagnetic spectrum consists of all the types of electromagnetic radiation arranged according to their frequency and wavelength. Each of the various colors of visible light has specific frequencies and wavelengths associated with them, and you can see that visible light makes up only a small portion of the electromagnetic spectrum. Because the technologies developed to work in various parts of the electromagnetic spectrum are different, for reasons of convenience and historical...
64.1K