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Yayın A survey of algorithms and architectures for H.264 sub-pixel motion estimation(World Scientific, 2012-05) Fatemi, Mohammad Reza Hosseiny; Ateş, Hasan Fehmi; Salleh, Rosli BinThis paper reviews recent state-of-the-art H. 264 sub-pixel motion estimation (SME) algorithms and architectures. First, H.264 SME is analyzed and the impact of its functionalities on coding performance is investigated. Then, design space of SME algorithms is explored representing design problems, approaches, and recent advanced algorithms. Besides, design challenges and strategies of SME hardware architectures are discussed and promising architectures are surveyed. Further perspectives and future prospects are also presented to highlight emerging trends and outlook of SME designs.Yayın On numerical design technique of wideband microwave amplifiers based on GaN small-signal device model(Springer, 2014-10) Köprü, Ramazan; Kuntman, Hulusi Hakan; Yarman, Bekir Sıddık BinboğaThis work presents an application of Normalized Gain Function (NGF) method to the design of linear wideband microwave amplifiers based on small-signal model of a device. NGF has been originally developed to be used together with an S-parameter (*.s2p) file, whereas this work enables the NGF to be able to work with explicit S-parameter formulae derived from the small-signal model of the device. This approach provides the designer to be able to use simple set of S-parameter equations instead of S-parameter file of the device. Representation of the device simply by several model equations not only eliminates the need of carrying large number of data but also provides the capability of equation-based easy, realistic and equispaced S-parameter data generation in any desired resolution in frequency axis without requiring interpolation. NGF is defined as the ratio of T and |S-21|(2), i.e. T-N = T/|S-21|(2), gain function of the amplifier to be designed and transistor forward gain function, respectively. Synthesis of output/input matching networks (OMN/IMN) of the amplifier requires two target gain functions in terms of T-N, to be used in two sequential non-linear optimization procedures, respectively. An amplifier with a flat gain of similar to 10 dB operating in 0.8-2.35 GHz is designed using a small-signal model of an experimental GaN-HEMT. Theoretical amplifier performance obtained in Matlab is shown to be in excellent agreement with the simulated performance in MWO (Microwave Office, AWR Inc.). A prototype low-power amplifier having a similar to 10 to 12 dB gain, operating in (0.9-1.5 GHz) is also produced and measured which yielded good performance results.Yayın Classification-based macroblock layer rate control for low delay transmission of H.263 video(IS & T - Soc Imaging Science Technology, 2003-07) Bayazıt, UluğPuri and Aravind's method of macroblock bit count estimation for video rate control is based on the classification of the macroblock data into discrete classes and assigning a unique non-linear estimate for each class and quantization parameter pair. This method stands apart from other methods in the literature, since the model of the bit count versus the quantization parameter relation, parameterized by macroblock variance, is a discrete model generated solely from measurements, We extend their technique for low-delay video rate control (tight buffer regulation) in two ways. We propose a strategy of near-uniform quantization parameter assignments to the macroblocks of a frame that can come close to maximizing an objective spatial quality function, such as PSNR, over the entire frame. We also adaptively update the quantization parameter assignments for the yet to be coded macroblocks, after the encoding of each macroblock, to compensate for any errors in the bit count estimation of the encoded macroblock. Our experiments demonstrate that the proposed rate control method can more accurately control the number of bits expended for a frame, as well as yield a higher objective spatial quality than the method adopted by TMN8.Yayın Design of a new low loss fully CMOS tunable floating active inductor(Springer New York LLC, 2016-12) Momen, Hadi Ghasemzadeh; Yazgı, Metin; Köprü, Ramazan; Saatlo, Ali NaderiIn this paper, a new tunable floating active inductor based on a modified tunable grounded active inductor is proposed. The multi regulated cascade stage is used in the proposed active structure to decrease the parasitic series resistance of active inductor, thus the Q factor enhancement is obtained. Furthermore, the arrangement of this stage leads to the smaller input transistor which determines active inductor’s self-resonance frequency and to be free of body effect which is crucial in sub-micron technology. Symmetrical design strategy has enabled both ports of the proposed floating active inductor to demonstrate the same properties. The Q factor and active inductor value are tuned with bias current and flexible capacitance (varactor), respectively. The self-resonance frequency of floating active inductor (~6.2 GHz) is almost the same as grounded prototype. In addition, the proposed active inductor also shows higher quality factor and inductance value compared to the conventional floating active inductor circuits. To show the performance of suggested circuit, simulations are done by using a 0.18 µm CMOS process, which demonstrates an adjustable quality factor of 10–567 with an inductance value range of 6–284 nH. Total DC power consumption and occupied area are 2 mW and 934.4 µm2, respectively.Yayın A design technique of 50 Ω terminated bandpass matching network and its implementation to a Y-shaped monopole antenna matching(Springer, 2016-12) Aydın, Çağatay; Atilla, Doğu Çağdaş; Köprü, Ramazan; Kılınç, Sedat; Karakuş, Cahit; Yarman, Bekir Sıddık BinboğaIn this paper, a 50 Ω terminated or in other words transformerless bandpass matching network design methodology and an implementation example are presented. The real frequency techniques are powerful numerical methods to design wideband lossless two-port networks such as filters, matching networks and amplifiers. In these techniques, the value of the termination resistance of the designed network could not be yielded as 50 Ω by numerical package. Hence, a transformer is also required for 50 Ω termination which is not practical for high frequency applications. By employing the proposed procedure, it is guaranteed to obtain transformerless bandpass matching network. Also in this study a wideband suspended monopole antenna is examined. The proposed antenna consists of two major elements; Y-shaped impedance matching plate and hemi-circular radiator. Moreover Y-shaped impedance matching plate connected to a feeding probe excites the suspended hemi-circular radiator via air gap. Consequently, a transformerless bandpass matching network is designed to filter and expand the operational frequency bandwidth of the proposed antenna. It has been observed that ideal circuit and the layout of the matching network simulation have good agreement.Yayın Metamutator applications: a quadrature MOS only oscillator and transconductance/transimpedance amplifiers(Springer New York LLC, 2016-06-18) Göknar, İzzet Cem; Yıldız, Merih; Minaei, ShahramNMOS based circuit realizations of a sinusoidal quadrature oscillator, a transconductance, a transimpedance amplifier are presented. All the circuits are constructed with a voltage-mode “Metamutator” consisting of an analog adder and a subtractor which is one of its possible realizations. The most important feature of the proposed circuits is their extremely simple structures containing only twelve NMOS transistors (six for adder, six for subtractor). Another significant advantage of the proposed circuits is that no external passive element is needed for the oscillator and only one resistor is used for each amplifier circuit; a variable resistor can provide gain adjustability. The post-layout simulations of all the proposed circuits have been executed using TSMC 0.25 µm process parameters with ±1.25 V power supply voltage.Yayın Current inverting metamutator, its implementation with a new single active device and applications(2018-10) Minayi, Elham; Göknar, İzzet CemA new kind of metamutator, namely "Current Inverting Metamutator", its realizations using different types of active blocks and some of its applications like voltage-mode universal biquadratic filter with three input and one output terminals are presented. The proposed circuits can realize all standard filters, namely, low-pass, band-pass, high-pass, notch and all-pass without passive component matching conditions. The proposed circuit offers the features of using grounded capacitors and orthogonal controllability of angular frequency and quality factor. Then a novel realization of metamutator with one active device, additive and differential IC (AD-IC) is proposed and implemented with twelve transistors only. The metamutator with AD-IC has the advantages: (1) of creating new realizations of memristors, capacitance multipliers, inductor simulators, frequency dependent negative resistors which can be used to make IC active filters, (2) less is the number (only one) of active devices, less is the amount of disparity, (3) no need to match passive component values.Yayın Ultra wideband matching network design for a V-shaped square planar monopole antenna(Cambridge University Press, 2014-12) Köprü, Ramazan; Kılınç, Sedat; Aydın, Çağatay; Atilla, Doğu Çağdaş; Karakuş, Cahit; Yarman, Bekir Sıddık BinboğaIn this paper, design, manufacture, and measurement of a wideband matching network for a broadband V-shaped square planar monopole antenna (V-SPMA) is presented. Matching network design is unavoidable in most cases even vital to facilitate a maximally flat power transfer gain for an antenna. In the work, a bandpass matching network (BPMN) design is done for a particular square monopole antenna with V-shaped coupling element that has essentially bandwidth increasing effect. Designed BPMN and the antenna forms a VSPMA-BPMN matched antenna structure. "real frequency technique" is employed in the BPMN design. BPMN prototype circuit has been constructed on an FR4 laminate with commercial microwave chip inductors and capacitors. Vector network analyzer gain and reflectance measurements of the matched antenna structure have shown highly compatible results to those of the theoretical design simulations along the passband (similar to 0.8-4.7 GHz). Furthermore, newly proposed distributed capacitor-resistor lossy model for microstrip lines used in the BPMN circuit have exhibited that it can successfully mimic the measured gain and reflectance performance of the matched structure in passband and even in stopband upto 8 GHz. Designed structure can be utilized as a one single wideband broadcasting medium suitable for many communication standards such as GSM, 3G, and Wi-Fi.Yayın Current inverting metamutator, its implementation with a new single active device and applications (vol 97, pg 15, 2019)(Springer, 2019-11) Minayi, Elham; Göknar, İzzet CemVoltage Inverting Metamutator (VIM) and Current.Yayın Method of moments (MoM) modeling of wave propagation inside a wedge waveguide(Applied Computational Electromagnetics Soc, 2014-08) Apaydın, Gökhan; Sevgi, LeventMethod of Moments (MoM) is used to model guided wave propagation inside a non-penetrable wedge waveguide and the results are validated against analytical mode-based exact solutions.
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