Vančo Litovski – författare

This book discusses synthesis of Gm-C filter for modern radio frequency systems. Analogue filters are an inevitable part of the chain of signal processing in modern radio and telecommunication systems. Among the technologies implemented for these purposes are the so-called Gm-C filters which are built of operational transconductance amplifiers and capacitors. This technology allows for integration of the filter into a CMOS system-on-chip so making it very attractive for application in low-power (battery operated) devices. The objective of this book is to achieve three goals: (1) to fully describe the circuit synthesis procedures for parallel, cascade, and a realization based on LC prototypes; (2) to make a thorough evaluation of the advantages and disadvantages of these methods and to recommend the “preferable” one; and (3) to create an extensive table of element values of cascaded Gm-C filters realizing the best-known low-pass filter functions. The book will influence the design community to embrace this technology even for non-communication applications.

This book provides a comprehensive overview of signal filtering, including an introduction, definitions of the terms and algorithms for numerical calculation of the properties of the transfer function in frequency and time domains. All the chapters discuss the theoretical background and explain the underlying algorithms including the iterative numerical procedures necessary to obtain the solutions.

It starts by considering polynomial filters, offering a broad range of solutions and introducing critical monotonic passband amplitude characteristics (CMAC). It also describes modifications to the classical Chebyshev and elliptic filters to overcome their limitations. In the context linear phase low-pass prototypes, it presents filters approximating constant group delay in the equi-ripple manner for the first time. Further, it discusses new procedures to improve the selectivity of all polynomial filters by introducing transmission zeros, such as filters with multiple transmissionzeros on the omega axis, as well as phase correction of selective filters for both low-pass and band-pass filters. Other topics explored include linear phase all-pass (exhibiting low-pass group delay approximation) filters; all-pass filters (exhibiting band-pass group delay approximation) with linear and parabolic phase synthesized directly as band-pass; high-pass, and band-stop amplitude characteristic frequency transformations to produce band-pass; and direct synthesis of linear and parabolic phase selective band-pass filters synthesized directly as band-pass. Lastly, for system (physical) synthesis, the book describes the algorithms and procedures for the following: cascade passive LC; active cascade RC; active parallel RC (for the first time); active parallel SC; Gm-C based on LC prototypes; and parallel IIR based on bilinear transformation of analog prototypes.

This book is mostly devoted to amplification of analogue signals. It covers different technologies (bipolar, MOS, and MES), and different frequency ranges but it always deals with small signals. Analogue signals processed in electronic system may have a wide variety of origins. Among them we have the signals coming from sensors (electro-mechanical, electro-magnetic, electro-chemical, electro-acoustic, electro-optical, etc.), the signals coming from antennas being produced by another electronic system or are simply cosmic produced, and signals that are generated within the electronic systems. The common property of most of the signals is their small amplitude. In many cases it is below a micro-volt. Since at the output of the system we most frequently need a high amplitude signal the main action undertaken in the electronic system before any further processing is to amplify.

This book discusses unified noise models of the broadest set of electronic components including, resistors, diodes, all types of transistors, and most types of opto-electronic devices. The noise, however, is a phenomenon which is inherent to any technology. It is omnipresent. It is obstructing every application and in many cases special actions must be undertaken to recognize the main function’s signal in the mistiness of the noise. The number of types of noise sources in electronics is almost unlimited. The book offers unique comprehensive approach to noise analysis in electronic circuits based on modified nodal analysis and the superposition theorem. It also encompasses a broadest set of low noise amplifier design procedures covering BJT, MOSET, MESFET, and HEMT technologies.