Digital signal processing applications mainly make use of multipliers which determine the overall performance of the system. The existing multiplier architectures are very complex and consume more time. Mitchell's Algorithm (MA) is a modest approach to compute the product using simple logarithmic operations and thus, achieving higher speed. Operand Decomposition (OD) reduces the switching activity and hence, achieves a better accuracy in fractional part calculation of logarithm. Divided Approximation (DA) and Table of Correction Values (TCV) are error correction approaches for MA which tries to follow the logarithmic curve more closely. Signed logarithmic multiplication using operand decomposition is proposed. The existing MA, DA and the proposed signed MA-OD, OD-DA, TCV are coded using Verilog HDL, simulated using ModelSim and synthesized using Xilinx XST. The simulated results are compared with respect to mean absolute error. The comparison results show that OD-DA and TCV significantly improve the accuracy of MA and found to decrease the mean absolute error of MA from around 5.36% to 1.7% and 1.33% respectively.

Implementation of operand decomposition in signed logarithmic multipliers

The scope of this paper is to design and simulate a novel circular split ring structure having simultaneous negative permittivity and permeability so called double negative metamaterial or left handed material. The DNG structure consists of five circular split ring resonators on one side of dielectric medium and a couple of circular wires on other side. The complex permittivity, permeability, impedance and refractive index are determined from simulated Scattering parameters using direct retrieval method. Simulations of DNG structure are carried out using CST MWS. MATLAB is used for verification of negative values of structure’s parameter.

/pdf/a-circular-split-ringdouble-negative-metamaterial-having-4lc365vxe3.pdf

A Circular Split Ringdouble Negative Metamaterial Having Simultaneous Negative Permittivity and Permeability

Orthogonal FrequencyDivisionMultiplexing(OFDM)isamulti-carriermodulationtechniquewhich dividestheavailable spectrumintomanycarriers.OFDMusesthespectrumefficiently comparedtoFDMAby spacing the channels much closer together and making all carriers orthogonal to one another to prevent interferencebetweenthecloselyspacedcarriers.ThemainadvantageofOFDMistheirrobustnesstochannel fadinginwirelessenvironment. TheobjectiveofthisworkistodesignandimplementanOFDMtransmitter and receiverusingMATLAB.Theworkconcentrates ondevelopingFastFourierTransform(FFT)andInverseFast FourierTransform(IFFT).The workalsoincludesindesigninga mappingmodule,serialtoparallelandparallelto serialconvertermodule.Thedesignuses16-pointsFFTandIFFTfortheprocessingmodulewhichindicatesthat theprocessingblockcontain16inputsdata.AllmodulesareimplementingusingMATLAB.

/pdf/implementation-the-technique-of-orthogonal-frequency-cbs47lk36e.pdf

Muhammad Tayyab Qaiser

Papers

A Circular Split Ringdouble Negative Metamaterial Having Simultaneous Negative Permittivity and Permeability

Implementation the Technique of Orthogonal Frequency Division Multiplexing Using 16-Point Fast Fourier Transform and Inverse Fast Fourier Transform