We study the temporal and spatial dynamics of the large amplitude and frequency modulation that can be induced in an intense, few cycle laser pulse as it propagates through a rapidly ionizing gas. Our calculations include both single atom and macroscopic interactions between the non-linear medium and the laser field. We analyze the harmonic generation by such pulses and show that it is spatiall...

Abstract The modulation of a voltage source inverter output causes losses and harmonic distortions on the load side DC-link capacitor due to discrete switching semiconductors. High-frequent pulses are digitally programmed control determine distortions. This paper presents an optimization in terms pulse- frequency-pattern selection for reducing while keeping minimal. In detail, fact that pulse f...

High-frequency ac link conversion offers a possible way to produce reduced-cost inverters for low-voltage dc sources such as fuel cells. The control complexity can be addressed by adapting pulse-width modulation (PWM) techniques. Here, a multi-carrier pulse-width modulation (PWM) approach is introduced as a convenient way to implement a high-frequency link inverter. The approach is a direct ext...

In this paper, we propose an orthogonal frequency division multiplexing–based (OFDMbased) underwater acoustic multimedia system. An essential feature of this system is that it offers greater power and schemes with significant error protection for the transmission of sensor data information requiring a higher quality of service (QoS). To realize maximum resource utilization or minimum total tran...

A fully integrated pulsewidth modulator for Class-S power amplifiers is presented. It consists of a triangular signal generator, a comparator and output buffer. The HBT BiCMOS design of PWM circuit is applied to the LTE frequency range, which converts digitally modulated 955MHz RF carrier with 2.87GHz sampling clock. This PWM shows an EVM 6.6%, a differential output voltage swing 1.35Vp-p with ...

Adaptive transmission technique adopting rectangularlypulsed orthogonally multiplexed modulation (OMM) signals is studied for the flat Rayleigh fading channel. By choosing spectrally efficient OMM signals in accordance with channel status under an error rate constraint, constantpower adaptive OMM systems are shown to significantly outperform the conventional constant-power adaptive orthogonal f...

This paper presents the implementation of Linear Frequency Modulation (LFM) pulse compression technique over acoustic waveguides at frequency range (2kHz--3kHz). The medium used for acoustic chirp propagation is air. Real time pulse compression was carried out over DSP kit (TMS320C6713). The obtained range from the compressed pulse accedes to the actual range of the target (sound source). The s...

We present results of an experimental study of the timing and phase dynamics in a mode-locked Ti:sapphire laser. By measuring the response of two widely spaced comb lines to a sinusoidal modulation of the pump power, we determine quantitatively the response of both the central pulse time and the phase. Because of the distinct response of the pulse energy, central frequency, and gain to the modu...

This paper presents optimal design of three-phase multilevel inverter for distributed power generation system using low frequency modulation and sinusoidal pulse width modulation as well. It is a modular type and it can be extended for extra number of output voltage levels by adding additional modular stages. The impact of the proposed topology is its proficiency to maximize the number of volta...

This paper addresses a comparative study of the spectral characteristics of four random-switching schemes that apply to the basic pulsewidth-modulation (PWM) dc/dc converters operating in discontinuous conduction mode (DCM). They include randomized pulse position modulation, randomized pulsewidth modulation, and randomized carrier frequency modulation with fixed duty cycle and with fixed duty t...