نتایج جستجو برای: frequency band switching
تعداد نتایج: 657131 فیلتر نتایج به سال:
We present a novel framework to analytically model dynamic waveband switching in a multi-granular optical network. The scalable solution consists in modeling each potential carrier of waveband tunnels independently by a Markov chain while modulating the rate of critical transitions, i.e. reserving a new waveband tunnel, by the waveband setup availability computed from the solution of other pote...
We compare the effectiveness of uniform versus non-uniform waveband switching under the dual cost metrics of switching requirements and fiber capacity. We consider a star topology and begin by characterizing the optimal performance frontier achievable under no restrictions on waveband sizing, and provide algorithms employing non-uniform waveband sizing that approach or achieve this optimum. We ...
We demonstrate that diode-switching can be used to introduce frequency agility into antennas produced by thermal transfer printing. Our particular example is a triangular Sierpinski fractal pattern with two PIN diodes to switch between operation optimised for the 800 MHz UHF band (diodes on) and the 2400 MHz ISM band (diodes off). Our measured results show an improvement in S11 in the UHF band ...
Cognitive radio (CR) is a promising technology that can enhance the radio spectrum utilization by enabling unlicensed users to exploit the spectrum in an opportunistic manner. However, the main challenge is to share the licensed spectrum without interfering transmissions of other licensed users. A CR node needs to vacate the spectrum upon detection of licensed users on a particular frequency ba...
Analysis and Simulation of ZVS Methods in Full Bridge Converters and Realization of a 3 KW Prototype
One of the difficulties with PWM switching converters is high switching loss and electromagnetic interference due to switching at non-zero voltage and current, which limits the operating frequency. In order to reduce the converter volume and weight (by increasing the frequency) and reducing switching losses, zero voltage and current switching methods are recommended. In this paper, four main ze...
Analysis and Simulation of ZVS Methods in Full Bridge Converters and Realization of a 3 KW Prototype
One of the difficulties with PWM switching converters is high switching loss and electromagnetic interference due to switching at non-zero voltage and current, which limits the operating frequency. In order to reduce the converter volume and weight (by increasing the frequency) and reducing switching losses, zero voltage and current switching methods are recommended. In this paper, four main ze...
A multi-band CMOS LC Quadrature Voltage Control Oscillator (QVCO) with minimum power consumption is developed to meet the phase noise and frequency band requirements of RFID, Zigbee and Bluetooth standards. To accomplish the multi-band receiving architecture at low power consumption, current switching technique with optimized cross-coupled transistor sizes has been used. A comprehensive analysi...
In this paper, a new method has been presented for differential protection of power transformers. In this approach, chaotic method has been used for distinguishing of inrush current from internal fault current of the transformer. The proposed algorithm has been designed based on analysis of harmonic components of the differential current of the transformer due to internal faults and inrus...
Traffic requirements on the Internet have changed from reliability to timeliness of delivery as different types of applications are being deployed on it. This situation has prompted the industry and IETF (Internet Engineering Task Force) to develop new protocols and techniques to meet the challenges. One of the important protocols developed is MPLS (Multi Protocol Label Switching) that allows n...
It is fairly well known that direct torque control (DTC) exhibits fast dynamic torque response, a property that originates in the fact that torque and flux is directly controlled by instantaneous space voltage vector, unlike field-oriented control. For this reason direct torque control gradually has been used in the field, eliciting quick response and high efficiency since its introduction in t...
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