Visible light communication (VLC) takes advantage of the widespread use light-emitting diodes (LEDs), and by modifying driver stage, LEDs are capable lighting transmitting information. One main drawbacks is low power efficiency due to modification LED stage in order add capability. Most research work related VLC toward task, whereas there a limited about improvement on efficiency. This article ...

In this paper, the reason for the relatively high distortion level of conventional class-D audio amplifiers is discussed. It is pointed out that the classical approach is insufficient for high performance applications. Therefore the importance of the matching between modulation and demodulation is demonstrated by simulation. 1. THE CLASS-D-AUDIO AMPLIFIER The concept of class-D amplifiers was i...

A method of analyzing switched-capacitor (SC) filters which incorporates a single-pole model of the operational amplifiers (op amp’s) is presented. Closed-form algebraic expressions for filter transfer functions in the z-domain are obtained which are computationally more efficient than time-domain methods. The necessity for including a frequency dependent model of the op amp rather than the com...

There are many different designs for audio amplifiers. Class-D, or switching, amplifiers generate their output signal in the form of a high-frequency square wave of variable duty cycle (ratio of on time to off time). The square-wave nature of the output allows a particularly efficient output stage, with minimal losses. The output is ultimately filtered to remove components of the spectrum above...

Switched capacitor power amplifiers (SCPAs) are a class of digital transmitters which have shown promising results for high linearity with good DE. Their is limited by AM-PM distortion, caused difference in output conductance switching and non-switching driver cells. Often, DPD required to transmit higher order modulation schemes. In this letter, cell implementation as an inverter drain resisto...

In this thesis, all-optical processing for future optical networks is studied by means of parametric processes in optical fibers. Parametric processes are nonlinear effects which arise in optical fibers when high-powered waves are properly placed at specific spectral positions. The properties of parametric processes are defined by the optical fiber characteristics, the power and the wavelength ...

Statement of Project Goals: 1. Design and assemble the Generation 0 (Gen 0) Health and Environmental Tracker (HET) testbed device to provide a baseline measurement platform to benchmark the improvements in Generation 1 (Gen 1) system in terms of power consumption, signal to noise ratio, sensor performance and size. The HET testbed includes a wristband and a chest patch. Obtain IRB approval and ...

<span>The work has presented duobinary modulation and predistortion techniques for the radio over fiber system enhancement achieving security level. Duobinary technique more compact modulated spectral linewidth with standard non return to zero code. Different NRZ/RZ rectangle shape employed that are namely exponential (ERS), Gaussian (GRS) different transmission bit rates. Switching bias ...