Variable domain transformation for linear PAC analysis of mixed-signal systems

This paper describes a method to perform linear AC analysis on mixed-signal systems which appear strongly nonlinear in the voltage domain but are linear in other variable domains. Common circuits like phase/delay-locked loops and duty-cycle correctors fall into this category, since they are designed to be linear with respect to phases, delays, and duty-cycles of the input and output clocks, respectively. The method uses variable domain translators to change the variables to which the AC perturbation is applied and from which the AC response is measured. By utilizing the efficient periodic AC (PAC) analysis available in commercial RF simulators, the circuit’s linear transfer function in the desired variable domain can be characterized without relying on extensive transient simulations. Furthermore, the variable domain translators enable the circuits to be macromodeled as weakly-nonlinear systems in the chosen domain and then converted to voltage-domain models, instead of being modeled as strongly-nonlinear systems directly

Discrete-Time Chaotic-Map Truly Random Number Generators: Design, Implementation, and Variability Analysis of the Zigzag Map

In this paper, we introduce a novel discrete chaotic map named zigzag map that demonstrates excellent chaotic behaviors and can be utilized in Truly Random Number Generators (TRNGs). We comprehensively investigate the map and explore its critical chaotic characteristics and parameters. We further present two circuit implementations for the zigzag map based on the switched current technique as well as the current-mode affine interpolation of the breakpoints. In practice, implementation variations can deteriorate the quality of the output sequence as a result of variation of the chaotic map parameters. In order to quantify the impact of variations on the map performance, we model the variations using a combination of theoretical analysis and Monte-Carlo simulations on the circuits. We demonstrate that even in the presence of the map variations, a TRNG based on the zigzag map passes all of the NIST 800-22 statistical randomness tests using simple post processing of the output data.Comment: To appear in Analog Integrated Circuits and Signal Processing (ALOG

The nonlinear class-E amplifier: a case study of harmonic balance applied to switched circuits

Nonlinear switched circuits are usually analyzed in the time domain. The use of frequency-domain methods to analyze the steady-state of switched circuits is usually restricted to linear circuits and, although Volterra series approaches are applied to the distortion of nonlinear switched circuits, the use of harmonic balance (HB) methods in nonlinear switched circuits seems to be marginal if not discarded. In this paper, we analyze the nonlinear class-E amplifier with an ideal switch by means of the HB method. We show how the switching function may be carefully chosen to improve the accuracy of the solution. When the circuit achieves actual class-E operation, the method converges better and is more accurate than classical timedomain methods. We conclude that the HB method is an alternative to time-domain methods that can be used to analyze the class-E amplifier in its expected operation mode.Postprint (published version

Optimization Of 5.7 Ghz Class E Power Amplifier For The Application Of Envelope Elimination And Restoration

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2007Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2007Rekabetin yoğun olduğu günümüzde tasarımcılar hafif, boyutları daha küçük ve düşük güçle çalışan yüksek performanslı ürün geliştirmenin yollarını aramaktadırlar. RF alıcı uygulamalarında güç kuvvetlendiricileri en fazla güç sarfiyatının olduğu bölümdür. Kablosuz iletişim sistemlerinde güç küvvetlendiricisi verimi maliyeti direkt olarak etkilemektedir. Teorik olarak %100 verim elde edilebilen E-sınıfı güç kuvvetlendiricileri transistorların açık/kapalı durum geçişlerinde güç sarfiyatını minimize edebilmektedir. Ayrıca çıkış gerilimi kaynak gerilimi ile doğrusal değişmektedir. Bu çalışmada E sınıfı güç kuvvetlendiricilerinin tasarım metodları ele alınmıştır. 5.7 GHz de çalışan birinde toplu devre elemanları, diğerinde transmisyon hattı elemanları kullanımış E sınıfı güç kuvvetlendiricileri tasarlanmıştır. Her iki devrede de %50 güç ekli verim (GEV) ve 500mW çıkış gücü elde edilmiştir. Sinyaldeki bozulmayı azaltmak için başvurulan doğrusallaştırma yöntemi Zarf Yoketme ve Tekrar Oluşturma metodudur. E sınıfı kuvvetlendiricinin Zarf Yoketme ve Tekrar Oluşturma yöntemi kullanılarak doğrusallaştırılmasıyla IMD bileşenlerinde 7.5 dB azalmış olup seviyesi gerçek işaretin 20dB altındadır.In today’s competitive, manufactures and product developers are seeking ways to build high performance devices that are lighter in weight, smaller in size and operating at lower power. In transceiver applications one module is responsible for a large portion of the power consumption - the power amplifier. The efficiency of the power amplifier has a direct impact on the cost of the wireless communication system. The class-E amplifier has a maximum theoretical efficiency of 100%. Class E power amplifiers have the ability to minimize power loss during on/off transitions of the transistor. Also, the output voltage varies linearly with the supply voltage. This thesis describes the design and the linearization methodology of the Class E amplifiers. Two class-E amplifiers operating at 5.7 GHz are presented. One of them is a lumped elements based circuit and the other is a transmission lines based circuit. Both circuit show good performance with 50% PAE and have 500mW output power. Envelope elimination and restoration is the linearization method chosen to achieve reduction of signal distortion. Linearization Class E PA using EER system provides an additional 7.5 dB reduction in intermodulation distortion products, achieving a minimum distortion level of 20 dB below the fundamental signals.Yüksek LisansM.Sc