Sharif Digital Repository

In last years, many researches are focoused on improving of suspension systems because of their importance in automotive afavourable performance. One of these advanced suspension systems are Magnetorheological suspension with nonlinear dynamic system and complicated behavior like Hysteresis Loops, so their modeling are notable.
In the first chapter as introduction, suspension systems and their aims are expressed briefly. Then Magnetorheological suspension structure and its function are mentioned. After review of researches that has done about its modeling and control , in the third chapter, different types of classic and generalized Prandtl-Ishlinskii models are introduced and... 

Increasing demand for high-speed and high-resolution ADCs as much as low-power ones and on the other hand, the obstacles in the way of reaching them make calibration and compensation methods more significant for obtaining ADCs with the better specs. Among the cases which need modification, the modification of C-2C-based SAR ADCs, which can decrease the power significantly, and the modification of time-skew error of time-interleaved ADCs, which is the main and the most challenging error in this type of ADCs, could be the two of the effective ways to making the State-of-the-Art ADCs. In this project for the first time, a novel compensation method for C-2C parasitic charges is proposed which... 

One of the most common problems encountered in multivariable systems is the interactions between the system inputs and outputs. Interaction causes difficulties in control of these systems. Hence reduction of interaction in multivariable systems is an important design objective. One way to do this is to employ a pre-compensator in the open loop systems. Several approaches with different design methods and optimization criterions have been proposed thus far. In this study the problem of interaction reduction for a square stable system is considered and a pre-compensator matrix is designed which reduces interactions in the interacting multivariable system.In this case the purpose is to use... 

In this thesis, we model and analyze coherent optical OFDM systems which are highly concerned as future fiber optic communication. To this end, we first introduce various applications of that in optical communication systems and investigate its probes and cones. In the rest of the thesis, we characterize the mathematical structure of the nonlinear phase noise and discuss the previous methods of compensation of that and propose some new ways of nonlinear phase noise compensation and equalization. And as we discuss each method we also investigate its computational complexity and BER performance. We propose three new phase noise compensation method, considering optical phase conjugation, we... 

The purpose of carrying out this Master thesis is to detect occurrence of CT saturation which leads to consecutive failures in operation of protective current transformers, as a major component in protection of power systems. The protective relay installed in the secondary side of the protective CT fails to act properly under occurrence of this phenomenon, and it doesn’t reflect proportionally the high value of fault currents passing through CT’s primary winding. As a consequence, faults become undetectable. Meanwhile, the proposed methods for detection of CT saturation must be reliable under a noisy condition, realizing that power systems have some inherent noises always available in the... 

Current transformers (CTs) are the most common current sensors in power system and use with measuring instruments and protective relays. Saturation of the protective CT threatens the proper operation of relays, while, the ratio error in a measuring CT directly reduces the accuracy of power system state estimation. In this dissertation, firstly, a test device has been introduced to identify the parameters of CT low-frequency model. Afterward, a digital compensator has been proposed to suppress the adverse effect of CT saturation. This compensator is capable to reproduce both the saturated inrush current and fault current that distinguishes it from other proposed methods. In addition, this... 

SRAM has a very wide application in different platforms including Cache Memory in Microcontrollers, etc. also SRAM is the first candidate for memory usage in every application needing High speed or static memory circuits. SRAM Cells are constructed by Minimum size transistors in each technology node and usually the newest technology nodes are used for building SRAM blocks for accommodating maximum number of SRAM Cells in a specific area. Going through smaller technology nodes, Leakage current and Process variations problem, creates serious difficulties in designing Low Power or High speed SRAM Memories and many academic and industrial works are done wishing for improvement in SRAM power...