23 research outputs found

    Design of Filter Using MOS Current Mode Logic

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    MCML (MOS Current Mode Logic) is a method used for the purpose of reducing the delay and power of the circuit. In high speed application this method is used to reduce the power. In this method the sleep transistor is inserted in series with the supply voltage (or) current source to reduce the power. Different power gating techniques are been used to reduce the static power and to improve the speed and efficiency of the circuit. In this paper, the filter can be designed by using MCML logic. The fourth order band pass filter by using MCML logic is introduced. In order to reduce the power and delay this method is proposed

    Phase Noise Analyses and Measurements in the Hybrid Memristor-CMOS Phase-Locked Loop Design and Devices Beyond Bulk CMOS

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    Phase-locked loop (PLLs) has been widely used in analog or mixed-signal integrated circuits. Since there is an increasing market for low noise and high speed devices, PLLs are being employed in communications. In this dissertation, we investigated phase noise, tuning range, jitter, and power performances in different architectures of PLL designs. More energy efficient devices such as memristor, graphene, transition metal di-chalcogenide (TMDC) materials and their respective transistors are introduced in the design phase-locked loop. Subsequently, we modeled phase noise of a CMOS phase-locked loop from the superposition of noises from its building blocks which comprises of a voltage-controlled oscillator, loop filter, frequency divider, phase-frequency detector, and the auxiliary input reference clock. Similarly, a linear time-invariant model that has additive noise sources in frequency domain is used to analyze the phase noise. The modeled phase noise results are further compared with the corresponding phase-locked loop designs in different n-well CMOS processes. With the scaling of CMOS technology and the increase of the electrical field, the problem of short channel effects (SCE) has become dominant, which causes decay in subthreshold slope (SS) and positive and negative shifts in the threshold voltages of nMOS and pMOS transistors, respectively. Various devices are proposed to continue extending Moore\u27s law and the roadmap in semiconductor industry. We employed tunnel field effect transistor owing to its better performance in terms of SS, leakage current, power consumption etc. Applying an appropriate bias voltage to the gate-source region of TFET causes the valence band to align with the conduction band and injecting the charge carriers. Similarly, under reverse bias, the two bands are misaligned and there is no injection of carriers. We implemented graphene TFET and MoS2 in PLL design and the results show improvements in phase noise, jitter, tuning range, and frequency of operation. In addition, the power consumption is greatly reduced due to the low supply voltage of tunnel field effect transistor

    Chaotic Oscillator Based Random Number Generator

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    Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2005Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2005Bu çalışmada, yüksek hızlı, sürekli zaman LC-kaotik osilatör tasarlanmış ve bu osilatörün çıkışları rasgele bit üretiminde kullanılmıştır. Hem Bipolar hem de MOS transistorlu osilatör versiyonları için devre deklemleri türetilmiştir. Bu denklemlerin nümerik denklem çözücü programlar yardımıyla çözülmesiyle kaotik osilasyonun sağlandığı görülmüştür. Devreler, Spectre spice simülatörü ve IHP SGB25VD 0.25µm SiGeC BiCMOS prosesi model parametreleri kullanılarak test edilmiştir. Rasgele sayı üretimi, osilatör çıkışlarının 2 farklı referansla karşılaştırılmasıyla elde edilmektedir. Oluşturulan bitlerin istatistiksel özelliklerini iyileştirmek amacıyla Von-Neumann algoritması tasarlanarak entegre edilmiştir. Üretilen çıkış bitleri periyodik olmadığından anlamlı bitlerin oluşma anlarını belirten bir saat işareti tanımlanmıştır. Rasgele sayı üretimi için gerekli olan alt bloklar yüksek hızlı çalışmaya uygun olacak şeklide Emetör Bağlamalı Lojik ve Akım Modlu Lojik aileleri kullanılarak tasarlanmıştır. Spectre simülatöründe gerçekleştirilen simülasyonlar, tasarlanan rasgele bit üretecinin yaklaşık 300Mbit/s hızında çıkış oluşturabildiğini göstermiştir. Çıkış işaretlerini cip dışına alabilmek amacıyla Akım Modlu Lojik çıkış sürecüleri tasarlanmıştır. Kaotik osilatör ve rasgele bit üreteci sistemi, IHP SGB25VD 0.25µm SiGeC BiCMOS prosesi ile gerçeklenmiş ve üretime gönderilmiştir. Çipin toplam güç harcaması 50mW mertebesindedir. Toplam kırmık alanı 1 mm x 0.5 mm’dir.In this study, a high speed continuous time LC-chaotic oscillator was designed and utilized as a random bit generator. Circuit equations were derived for both MOS transistor and BJT versions. These equations were solved by using numeric solvers, and chaotic oscillation was observed. Spectre circuit simulator was used as the simulator. Circuits were verified by using IHP’s SGB25VD 0.25µm SiGeC BiCMOS process. To generate successive ‘1’s and ‘0’s, two comparators with different references were used. A well-known Von-Neumann de-skewing algorithm was also implemented in order to improve statistical properties of the generated bit stream. The clock signal was constructed using the outputs of the comparators in order to define the bit generation events. The random bit generation sub-blocks were implemented as bipolar Emitter Coupled Logic (ECL) and Current Mode Logic (CML) gates. Spectre simulations showed that the average throughput of the designed random bit generator is approximately 300Mbit/s. The CML output drivers were designed to output the generated data and clock signals. The whole system, including the BJT chaotic oscillator and the random bit generation sub-blocks, were implemented in IHP’s SGB25VD 0.25µm SiGeC BiCMOS process. The chaotic oscillator and the random bit generator block consume approximately 50mW power under typical conditions. Total area of the chip is 1 mm x 0.5 mm.Yüksek LisansM.Sc

    New design methodologies for microwave oscillators based on negative impedance. Study and development of the solution space concept

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    The topic of this thesis concern the study of new design methodologies for microwave oscillators based on negative impedance and LC resonant circuits. For this class of systems, it is not ordinary possibile to predict the stationary behaviour of the circuit without use non linear analysis methodologies, but these are very e complicated and not very helpful for the design. Indeed, for microwave circuits, the design technique is that of reflection parameters "S" that describe with accuracy only linear systems and shaped them in response to small signal conditions. Therefore the only way to design a good oscillator is through experience and try and error procedures. By Developping a CAD tool that allows to represent in graphical form all possibile solutions (The Solution Space) for which an amplifier and two passive networks (feedback and loads) are able to give a negative impedance looking by other port, a new design methodology has been presented. This methodology use only S small signal parameters and allows to guarantee the start-up for a given frequency when the other port is colsed with a proper LC circuit, and moreover is able to predict the behaviour of the system in steady state. Then became easily possibile to design the system in order to maximize the output power and reduce the phase noise. The proposed methodology is then successfully used in the design of a 38GHz VCO. ------------------------------------------------------------------------------------------------------------------------ L’oggetto di questa tesi è lo studio di nuove metodologie di progetto per oscillatori a microonde costituiti da un blocco di impedenza negativa e un circuito risonante LC. Per tale classe di sistemi la difficoltà nella procedura di progettazione consiste nel non aver ancora trovato una chiave che permettesse di prevederne il comportamento a regime senza l’utilizzo di metodi di analisi non lineare, notoriamente molto complicati e poco utili per il progetto. Infatti, per i circuiti a microonde, la tecnica universalmente adottata è quella dell’utilizzo dei parametri di riflessione “S” che descrivono con veridicità solamente sistemi lineari e modellati in risposta a condizioni di piccolo segnale. Non esistono quindi metodologie per gli oscillatori che vengono progettati secondo esperienza procedure del tipo try and error. Sviluppando al calcolatore un tool che permette la rappresentazione grafica dell’insieme delle soluzioni (Spazio delle Soluzioni) per cui un sistema costituito da amplificatore e reti passive di reazione e di carico possono generare una resistenza negativa ad una porta si è messa appunto una metodologia che non solo garantisce le condizioni di innesco del sistema quando la restante porta viene chiusa da un opportuno circuito risonante, di cui è possibile estrarre le caratteristiche, ma anche di prevedere unicamente utilizzando i parametri a piccolo segnale, il comportamento del sistema a largo segnale e di progettare l’oscillatore in maniera scientifica secondo le specifiche desiderate. La metodologia proposta viene quindi applicata con successo al progetto di un VCO a 38GHz

    Large space structures and systems in the space station era: A bibliography with indexes (supplement 04)

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    Bibliographies and abstracts are listed for 1211 reports, articles, and other documents introduced into the NASA scientific and technical information system between 1 Jul. and 30 Dec. 1991. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems

    Laser Systems for Applications

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    This book addresses topics related to various laser systems intended for the applications in science and various industries. Some of them are very recent achievements in laser physics (e.g. laser pulse cleaning), while others face their renaissance in industrial applications (e.g. CO2 lasers). This book has been divided into four different sections: (1) Laser and terahertz sources, (2) Laser beam manipulation, (3) Intense pulse propagation phenomena, and (4) Metrology. The book addresses such topics like: Q-switching, mode-locking, various laser systems, terahertz source driven by lasers, micro-lasers, fiber lasers, pulse and beam shaping techniques, pulse contrast metrology, and improvement techniques. This book is a great starting point for newcomers to laser physics
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