نتایج جستجو برای: pulse modulation
تعداد نتایج: 231550 فیلتر نتایج به سال:
با ظهور و گسترش سیستم های مخابراتی با عرض پالس بسیار باریک، پهنای باند بسیار وسیع، محدودیت پهنای باند و سرعت قطعات الکترونیکی موجود، استفاده از بسیاری از ساختار های آشکار سازی ناهمدوس شناخته شده پیشین با دشواری روبرو است و طراحی گیرنده مناسب در اینگونه سیستم ها از اهمیت ویژه ای برخودار است. در حوزه رادیویی، طراحی گیرنده-های ساده و کم مصرف در مخابرات فراپهن باند (uwb) بدون استفاده از مکانیزم های...
The effect of self-phase modulation in chirped-pulse amplification is investigated. A numerical model is used to predict the effects of phase modulation on pulse recompression, and experimental results are presented that agree well with the calculations. We show that even moderate self-phase modulation can significantly distort the recompressed pulse after amplification, thereby reducing the pe...
Sinusoidal pulse width modulation is a popular modulation for most alternating current induction motor. It only requires fewer calculations and is easy to implement. However, the shortcomings of using it are low DC voltage utilization, and poor inverter transmission capability. In recent years, there is an increasing trend and more research concentration of using space vector pulse width modula...
This Paper Presents a comparative study of Constant Switching frequency Multicarrier Pulse width Modulation and Variable Switching frequency Multicarrier Pulse width Modulation. The emergence of Multilevel converter has been in increase since the last decade . These new type of converters are suitable in high voltage & high power application due to their ability to synthesize waveforms with bet...
One of the ways to implement UWB system is pulse radio IR method, which based on transmission very short (on order several nanoseconds and picoseconds) low – power pulses. The paper considers types modulation in short-pulse signals ultra-wideband communication: binary pulse-position Binary PPM, format with two values signal amplitude, two-phase Bi-Phase Modulation.
Due to the growing demand for higher bandwidth, employing optical devices instead of electronic devices in data transmission systems has attracted much attention in recent years. Optical switches, modulators and wavelength converters are a few examples of the required optical devices. CMOS compatible fabrication of these devices, leads to much more growing of this technology. Optical pulse comp...
Intensity modulation with direct modulation (IM/DD) favors low duty cycle modulation schemes such as pulse position modulation (PPM) and multiple PPM(MPPM).In this paper,the channel model over IM/DD is introduced. Then, a brief summary is given about some of the modulation techniques used in this area. Finally, some of the pulse position based coded modulation techniques are rewiewed.
lead forms the complexes with xylenol orange in the basic solution. an adsorptivedifferential pulse stripping method for the determination of lead is proposed. the procedureinvolves an adsorptive accumulation of lead on a hanging mercury drop electrode (hmde) inthe presence of xylenol orange, followed by reduction of adsorbed lead by voltammetric scanusing differential pulse modulation. the opt...
This paper presents analysis, simulation and implementation of Space vector pulse width modulation (SVPWM) inverter. Principles of the SVPWM is introduced and analyzed. Modeling of the switching intervals and control signal generators are introduced. Implementation and Experimental results of SVPWM inverter are presented to realize the validity of the SVPWM technique. Key-Words: Inverter – Puls...
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