Design and Implementation of a Low-noise Direct Conversion Mixer with LO-2LO Method

, M.Sc. Thesis Sharif University of Technology Kalami, Milad (Author) ; Medi, Ali (Supervisor)

Abstract

In this thesis, we try to design and implement a low noise, low power consumption CMOS direct conversion mixer with LO-2LO topology. Direct conversion mixers have two differential I,Q outputs. Because of zero intermediate frequency, flicker noise is critical. This mixer is designed for UHF band in TSMC CMOS 0.18µm technology. Total current consumption of I,Q mixer is less than 3mA .Voltage conversion gain is about 23 dB and DSB noise figure is less than 3.5 dB. Some conventional thermal and flicker noise cancellation has been used simultaneously to reduce noise figure. New noise cancellation techniques are proposed to get further improvement in noise figure with negligible extra current...

A novel adaptive LMS-based algorithm considering relative velocity of source

, Article 2010 7th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2010, 21 July 2010 through 23 July 2010, Newcastle upon Tyne ; 2010 , Pages 10-14 ; 9781861353696 (ISBN) Shirvani Moghaddam, S ; Shirvani Moghaddam, M ; Kalami Rad, R ; Sharif University of Technology

2010

Abstract

In this paper a new least mean square (LMS) based adaptive weighting algorithm is proposed. It is appropriate for antenna array systems with moving targets and mobile applications. The essential goal of this algorithm is to reduce the complexity of weighting process and to decrease the time needed for adjusting the antenna radiation pattern. The main lobe of antenna will be adjusted in the direction of desired signal (main signal) and nulls pointed in the direction of undesired signals (interference signals). By predicting the relative velocity of source, the next location of the source will be estimated and the array weights will be determined using LMS algorithm before arriving to the new...

CMA-based adaptive antenna array digital beamforming with reduced complexity

, Article 2010 7th International Symposium on Communication Systems, Networks and Digital Signal Processing, CSNDSP 2010, 21 July 2010 through 23 July 2010, Newcastle upon Tyne ; 2010 , Pages 327-331 ; 9781861353696 (ISBN) Shirvani Moghaddam, S ; Shirvani Moghaddam, M ; Kalami Rad, R ; Sharif University of Technology

2010

Abstract

Reducing the computational complexity as well as convergence time is the main task of adaptive antenna array processing. This article proposes an improved algorithm for estimating the weights of adaptive array elements based on Constant Modulus Algorithm (CMA). In this new type of algorithm, those weights that have higher effect on the radiation pattern will be estimated and antenna pattern will be adjusted by changing these weights. In this research, 3 new algorithms are proposed. By simulating these algorithms and comparing them with conventional full weight CMA, finally new algorithm that has a reduced complexity and an acceptable performance at different signal to noise ratios (SNRs) is...

Does the short-term boost of renewable energies guarantee their stable long-term growth? Assessment of the dynamics of feed-in tariff policy

, Article Renewable Energy ; Volume 159 , October , 2020 , Pages 1252-1268 Milad Mousavian, H ; Hamed Shakouri, G ; Mashayekhi, A. N ; Kazemi, A ; Sharif University of Technology

Elsevier Ltd 2020

Abstract

Feed-in tariff (FiT) is one of the most efficient ways that many governments throughout the world use to stimulate investment in renewable energies (REs) technology. For governments, financial management of the policy could be challenging as it needs a considerable amount of budget to support RE producers during the long remuneration period. In this paper, it has been illuminated that the early growth of REs capacity could be a temporary boost. And the socio-economic structure of the system will backlash the policy if some social mechanisms are not considered. Social tolerance for paying REs tax and potential investors’ trust emanated from budget-related mechanisms -which have rarely been...

The Geometry of the Group of Symplectic Diffeomorphisms

, M.Sc. Thesis Sharif University of Technology Kalami Yazdi, Ali (Author) ; Eftekhary, Eiman (Supervisor) ; Esfahani Zadeh, Mostafa (Supervisor)

Abstract

In this thesis, we first define the pseudo-distance p on the group of Hamiltonian diffeomorphisms.Using the concept of displacement energy, we show that the pseudo-distance p is degenerate and if the manifold is closed, p will be zero for each p = 1; 2; 3; : : : Then, we introduce Lagrangian submanifolds and prove that if L R2n is a rational Lagrangian submanifold, we have the following inequality e(L) ≥ 1γ(L). : Finally, using the above inequality and the concept of displacement energy, for M = R2n we prove that 1 is non-degenerate. Therefore, the hypothesis for 1 to be a metric, are satisfied. This metric is called Hofer’s metric