Continuousand discrete-time switching audio power amplifiers are studied both with and without feedback. Pulse-width modulation (PWM) and sigma–delta modulation (SDM) amplifier configurations are simulated and their interrelationship is described using linear phase modulation (LPM) and linear frequency modulation (LFM). Distortion generation encountered when applying negative feedback to PWM is...

This paper proposes new lossless passive soft switching methods for inverters developed from a synthesis procedure applicable to all PWM converters. The lossless passive soft-switching converter properties and synthesis procedure are described and extended here for inverters. Promising half-bridge and full-bridge soft-switching inverter examples are shown from the synthesis results. The voltage...

The Inertially Stabilized Rifle is a new stabilized rifle system that can eliminate the disturbances induced by the shooter. Recurve actuator is used in this system to provide the precise movement of the rifle barrel. In such a portable device, only low voltage electrical sources are available yet the piezoelectric actuator needs high voltage to drive the actuator. The actuators consume little ...

Abstract: Telescopic amplifiers are often preferred for their large DC gain, low power dissipation and low flicker noise. On the other side, they suffer from serious problems like poor input common mode range and output swing. In this work, a simple technique to improve the input common mode range of telescopic structure is presented. To achieve this, two telescopic amplifiers using complementa...

In this paper, we investigate the parameters affecting Total Harmonic Distortion (THD) and Power Supply Rejection Ratio (PSRR) in PWM Class D Amplifiers (CDAs) on the basis of linear models with feedback. From our mathematical analysis, we show that the THD of a PWM Class D amplifier with feedback can be improved by increasing the gain of the integrator through adding another amplifier at the o...

An Efficient Supply Modulator for Linear Wideband RF Power Amplifiers. (August 2011) Richard Turkson, B.Sc., Kwame Nkrumah University of Science and Technology Chair of Advisory Committee: Dr. Jose Silva-Martinez Radio Frequency (RF) Power Amplifiers are responsible for a considerable amount of the power consumption in the entire transmitter-receiver (transceiver) of modern communication system...

Self-assembled quantum dot (QD) Semiconductor Optical Amplifiers (SOAs) are believed to have faster carrier recovery times than conventional multiple quantum well, or bulk SOAs. It is therefore of interest to study the carrier dynamics of QD SOAs to assess their potential as ultrafast nonlinear devices for switching and signal processing. In this work we report experimental characterization of ...

QIN, JIFENG. A Low Noise, High Efficiency Envelope Modulator Structure for EDGE Polar Modulation. (Under the direction of Dr. Alex Q. Huang). Dynamic supply of power amplifiers in wireless transmitters can overcome the linearity-efficiency tradeoff issue in power amplifiers design, and envelope modulator is the key block in the dynamic supply system, low noise and high efficiency implementation...

A photonic ATM switch based on wavelengthdivision multiplexing will include several lossy passive devices, erbium-doped fiber amplifiers, and semiconductor optical amplifiers (SOAs) in a cascade configuration for fast switching of ns order. Its level diagram, which is very different from those of optical transmission links, has not been adequately studied. This paper investigates the concept of...

GaN-based high electron mobility transistors (HEMTs) are among the most promising devices for high power radio frequency (RF)/microwave (MW) and switching applications owing to their high breakdown voltage, high electron density, and high electron saturation velocity.[1,2] In fact, GaN HEMTs are currently employed in RF/MW high power amplifiers, low-noise amplifiers (LNA), and RF switching modu...