The multilevel inverters have become more popular during the recent years. The multilevel inverters are applied in many industrial applications such as static VAR compensators, AC power supplies, drive systems, active power filters, etc. The topologies of multilevel inverter have several advantages such as low distortion in output voltage with relative low switching frequency, low harmonic and ...

In this paper we propose a suitable reference wave for Pulse Width Modulation (PWM) AC Drives. Staircase reference waves whose levels are calculated to eliminate certain harmonics are studied and a certain staircase reference waveform with L levels is constructed. When L is made very large in limit, this staircase waveform approaches a continuous one which is called Quasine (Quasi + Sine). This...

We report on a cross-gain and cross-phase modulation experiment in an InGaAsP semiconductor optical ampliier. For 150 fs pulses we observe large pulse broadening and pulse break-up resulting in performance limitations for ultrafast switching devices. Introduction: Semiconductor optical ampliiers (SOA's) are key components in high-speed optical communication networks in functions as optical swit...

We propose a digital driving technique using pulse-density modulation (PDM) for an active-matrix organic light-emitting diode (AMOLED) to effectively suppress the false image contour in conventional pulsewidth modulation (PWM) while achieving considerably low operating frequency. A compact first-order digital modulator provides the PDM signal to the panel. A 2.2-inch QVGA AMOLED system using th...

When a probe pulse copropagates with a pump pulse inside an optical fiber, the two can interact through cross-phase modulation. It is shown that an interplay between the effects of group-velocity dispersion and cross-phase modulation can lead to optical wave breaking that manifests as rapid oscillations near the leading or the trailing side of the probe pulse. Qualitative features of this new k...

In modern world of communication system, a coded M-ary pulse position modulation (PPM) scheme for transmitted reference ultra-wideband (TR-UWB) systems is proposed. The modulation level M in conventional M-ary PPM TR-UWB scheme, is defined only with a number of possible pulse positions Z. So, Z radio frequency (RF) wideband delay lines are required in order to map data bits into the proper puls...

We investigated on the influence of a temporally dispersive Kerr effect on the modulation instability and the propagation of solitary wave pulse. The modulation instability gain is derived and compared with numerical calculations. The role of nonlinear response time on reshaping the solitary pulse is examined. 2008 Elsevier B.V. All rights reserved.

Photoplethysmography (PPG) technology has been used to develop small, wearable, pulse rate sensors. These devices, consisting of infrared light-emitting diodes (LEDs) and photodetectors, offer a simple, reliable, low-cost means of monitoring the pulse rate noninvasively. Recent advances in optical technology have facilitated the use of high-intensity green LEDs for PPG, increasing the adoption ...