نتایج جستجو برای: width modulation

تعداد نتایج: 210664  

2008
Ehud Nakar Tsvi Piran

We analyze a sample of bright long bursts and find that the pulses duration have a lognormal distribution while the intervals between pulses have an excess of long intervals (relative to lognormal distribution). This excess can be explained by the existence of quiescent times, long periods with no signal above the background. The lognormal distribution of the intervals (excluding the quiescent ...

2008
Patrick Weltevrede Simon Johnston

The observed fraction of pulsars with interpulses, their period distribution and the observed pulse width versus pulse period correlation is shown to be inconsistent with a model in which the angle α between the magnetic axis and the rotation axis is random. This conclusion appears to be unavoidable, even when non-circular beams are considered. Allowing the magnetic axis to align from a random ...

Journal: :Optics letters 2010
Gastón A Ayubi José A Ferrari

We comment on a recent Letter [Opt. Lett. 35, 4121 (2010)], in which the authors discuss an optimal pulse-width modulation (OPWM) method for sinusoidal fringe generation. We consider that the comparison of the squared binary method (SBM) and the sinusoidal pulse-width modulation (SPWM) method has considerable deficiencies.

2004
Shawn Kuo Michael H. Perrott Arthur C. Smith

Currently, the cellphone industry is moving towards an integrated CMOS solution for power amplifiers. Cheaper phones for consumers and better bottom lines for companies are the result of this. The goal of this thesis is to investigate the use of pulse width modulation in a high efficiency integrated CMOS power amplifier for a wireless application. Though high efficiency CMOS power amplifiers ex...

Journal: :IEICE Transactions 2011
Xin Zhang Yu Pu Koichi Ishida Yoshikatsu Ryu Yasuyuki Okuma Po-Hung Chen Takayasu Sakurai Makoto Takamiya

In this paper, a novel switched-capacitor DC-DC converter with pulse density and width modulation (PDWM) is proposed with reduced output ripple at variable output voltages. While performing pulse density modulation (PDM), the proposed PDWM modulates the pulse width at the same time to reduce the output ripple with high power efficiency. The prototype chip was implemented using 65 nm CMOS proces...

Journal: :IEEE Trans. Industrial Electronics 2000
Kwok-kuen Tse Henry Shu-Hung Chung Ron Shu-Yuen Hui H. C. So

A comparative investigation on the use of random modulation schemes for dc/dc converters is presented. The modulation schemes under consideration include randomized pulse position modulation, randomized pulsewidth modulation (PWM), and randomized carrier-frequency modulation with fixed and variable duty cycle. The paper emphasizes the suitability and applicability of each scheme in dc/dc conver...

2013
RICHA ADLAKHA

Multilevel inverters with space vector pulse width modulation strategy are gained importance in high power high performance industrial drive applications.This paper presents a simplified space vector PWM method for a two-level and three level inverter The threelevel inverter has a large number of switching states as compared to two level inverter. In the proposed scheme, three-level space vecto...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی امیرکبیر(پلی تکنیک تهران) - دانشکده مهندسی برق 1386

بیشترین تعداد مورد استفاده در حال حاضر از ماشینهای چند فاز، ماشین القایی فاز شکسته (spim) می باشد. spim دارای دو مجموعه سیم پیچی استاتور سه فاز می باشد که با هم از نظر الکتریکی 30 درجه اختلاف فاز دارند. عیب اصلی spim وجود جریانهای هارمونیکی هستند که در تولید شار فاصله هوایی نقشی ندارند و فقط در استاتور ماشین می چرخند. به منظور بدست آوردن پاسخ سریع گشتاور ابتدا روش کنترل مستقیم گشتاور (dtc) بر ا...

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