Narrow Results

Negative impedance converter circuits (NICs) are important building blocks in design and manufacturing of analog and mixed mode integrated circuits. In this paper, a catalogue of single-current feedback amplifier-based negative impedance converter circuits having impedance scaling properties is proposed. Various examples are presented to illustrate the versatility of the proposed NIC circuits.

In this paper, eight new Frequency Dependent Negative Resistance (FDNR) circuits using two current conveyors or inverting current conveyors or a combination of the two types are introduced. The proposed circuits are canonic and they use two grounded capacitors and one floating resistor. The generation of grounded capacitor minimum passive component oscillators from the FDNR circuits is also considered. It is found that two of the recently reported attractive oscillators are among the family of the generated oscillator circuits. Additional six new oscillator circuits based on the FDNR circuits are introduced in this paper. Spice simulation results using technology: SCN 05 feature size 0.5 μm, MOSIS Vendor: AGILENT to demonstrate the practicality of the proposed oscillators are included.

This paper presents a generalization of six well-known quadrature third-order oscillators into the fractional-order domain. The generalization process involves replacement of three integer-order capacitors with fractional-order ones. The employment of fractional-order capacitors allows a complete tunability of oscillator frequency and phase. The presented oscillators are implemented with three active building blocks which are op-amp, current feedback operational amplifier (CFOA) and second generation current conveyor (CCII). The general state matrix, oscillation frequency and condition are deduced in terms of the fractional-order parameters. The extra degree of freedom provided by the fractional-order elements increases the design flexibility. Eight special cases including the integer case are illustrated with their numerical discussions. Three different phases are produced with fixed sum of $2\pi$ which can be completely controlled by fractional-order elements. A general design procedure is introduced to design an oscillator with a specific phase and frequency. Two general design cases are discussed based on exploiting the degrees of freedom introduced by the fractional order to obtain the required design. Spice circuit simulations with experimental results for some special cases are presented to validate the theoretical findings.

In this paper, the method for the design automation of a narrow band-pass amplifier, and hence the amplifier tuned oscillator is discussed. A fixator approach is utilized in this method to design the narrow band-pass amplifiers and a reference circuit is required for this process. The fixator–norator pair helps to generate an extra sub-circuit, generally the feedback network; the addition of this sub-circuit in the actual amplifier circuit will modify the frequency response of the amplifier. The amplifier now behaves like an active narrow band-pass filter, which exactly follows the frequency response of the model circuit. This can be turned into an oscillator by providing positive feedback. Such a circuit possesses independent frequency and amplitude control. Hence, the re-designed circuit can be employed as an active filter or an oscillator at the selected center frequency. In addition to the technical merits, the proposed method has pedagogical importance. Few case studies are worked out in this paper to demonstrate the method.

This paper presents the structure and operational principles of high-frequency electronically controllable sinusoidal oscillators employing current-feedback operational amplifiers (CFOAs) with externally accessible compensation node $z$ as active components. The resonant circuits in the oscillators are connected to the terminal $z$, and for them in the selective network varactor diodes or varicaps as the variable capacitances are utilized, which are controlled by external DC voltage. Based on an analysis of the proposed circuit configurations, analytical expressions for the characteristic equation in a steady-state mode of operation and formulas for the basic electrical parameters have been obtained. In order to verify the functionality of the proposed electronic circuits and the effectiveness of the derived analytical expressions, an experimental and simulation study of sample electronic circuits with commercially available integrated circuit CFOAs AD844 in the frequency range up to about 10MHz is performed. The obtained results for the studied electronic circuits confirm the theoretical studies and hypotheses, and the comparative analysis shows that the maximum value for the relative error does not exceed 10%, which is acceptable considering the tolerances of the technological parameters of the used passive and active elements.

In many integrated circuit applications, where large passive resistors are prohibited, a tunable active resistor is necessary. This paper presents a compact and wide-range voltage-controlled grounded resistor that employs MOS transistors only. The design’s foundation is an active adjustable resistor that controls the NMOS transistor’s mode of operation. The proposed design is implemented using 0.18$\mu$m TSMC CMOS technology and is validated through post-layout simulations conducted in the Cadence Virtuoso environment. Furthermore, a tunable high-pass filter utilizing the proposed active resistor is also shown. The circuit is powered by 1.5V DC. According to the simulation findings, the resistance varies between 33k $\mathrm{\Omega }$ and 36G $\mathrm{\Omega }$, for an input voltage range $-$0.7–0.6v.

A system that consists of two impacting oscillators with damping has been considered in this paper. The goal of the studies was to determine the relation between the values of resonant frequencies of the oscillators and the existence of their stable periodic motion. This paper indicates various origins of the periodicity of motion and offers a some advice to the designers of systems with impacts. Especially, the results of the considerations point out some potentially dangerous consequences of the improper value of the resonant frequencies ratio.

In this paper, we study the synchronization properties of random geometric graphs. We show that the onset of synchronization takes place roughly at the same value of the order parameter as a random graph with the same size and average connectivity. However, the dependence of the order parameter on the coupling strength indicates that the fully synchronized state is more easily attained in random graphs. We next focus on the complete synchronized state and show that this state is less stable for random geometric graphs than for other kinds of complex networks. Finally, a rewiring mechanism is proposed as a way to improve the stability of the fully synchronized state as well as to lower the value of the coupling strength at which it is achieved. Our work has important implications for the synchronization of wireless networks, and should provide valuable insights for the development and deployment of more efficient and robust distributed synchronization protocols for these systems.

Memristors are gaining increasing interest in the scientific community for their possible applications, e.g. high-speed low-power processors or new biological models for associative memories. Due to the intrinsic nonlinear characteristic of memristive devices, it is possible to use them in the design of new dynamical circuits that are able to show complex behavior, like chaos. In this paper, two new memristive chaotic circuits are presented discussing, in particular, an approach based on Cellular Nonlinear Networks for the implementation of the memristive device. The approach investigated in this paper allows to obtain memristors with common off-the-shelf components and to observe the onset of new chaotic attractors in nonlinear circuits with memristors. Furthermore, the circuits presented in this paper, being the first examples of memristive chaotic circuits based on CNNs, can be considered as the link between the three inventions by Leon O. Chua, i.e. the memristor, the first chaotic electronic circuit and Cellular Nonlinear Networks.

In this paper, a new electro-mechanical chaotic oscillator is presented. The system is based on the motion of the metal tip of a beam in a double-well potential generated by two magnets, and works thanks to the vibrations generated in the flexible mechanical structure by two rotating coils that produce noise-like signals. As the source of vibration is internal, the system may be considered an autonomous oscillator. Chaotic motion is experimentally observed and verified with a mathematical model of the phenomenon.

Dry-friction contacts in mechanical oscillators can be modeled using nonsmooth differential equations, and recent advances in dynamical theory are providing new insights into the stability and uniqueness of such oscillators. A classic model is that of spring-coupled masses undergoing stick-slip motion on a rough surface. Here, we present a phenomenon in which multiple masses transition from stick to slip almost simultaneously, but suffer a brief loss of determinacy in the process. The system evolution becomes many-valued, but quickly collapses back down to an infinitesimal set of outcomes, a sort of “micro-indeterminacy”. Though fleeting, the loss of determinacy means masses may each undergo different microscopic sequences of slipping events, before all masses ultimately slip. The microscopic loss of determinacy is visible in local changes in friction forces, and in creating a bistability of global stick-slip oscillations. If friction forces are coupled between the oscillators then the effect is more severe, as solutions are compressed instead onto two (or more) macroscopically different outcomes.

Technical analysis helps investors to better time their entry and exit from financial asset positions. This methodology relies solely on past information on financial assets price and volumes to predict a financial asset’s future price trend. Modern research has established that combined with other sentiment measures such as social media, it can outperform the standard buy and hold strategy. Moreover, it has been documented that novice and professional investors technical analysis in their investing strategy. An experienced investor should combine fundamental analysis and technical analysis for better trading results. Programmers use technical analysis to create algorithmic trading systems that learn and adapt to the changing trading environments and perform trading accordingly without human involvement. There are hundreds of technical tools offered by known trading platforms. investors must use specific tools that fit their trading style and risk adoption. Moreover, different financial assets such as stocks, exchange trade funds (ETFs), cryptocurrency, futures, and commodities demand different sets of tools. Furthermore, investors should use these tools according to the time frame they use for trading. This paper will discuss different technical tools that are used to help traders of different time frames and different financial assets to achieve better returns over the traditional buy and hold strategy.

Time and frequency measurements of a high frequency oscillator need the comparison to a reference oscillator: the physical units of the measurement are the integers and the relevant approach is analytical number theory. We show this in the context of the moon-sun calendar discovered in ancient Greece and in the context of a communication receiver. It is shown that the resets in time measurements are governed by continued fraction expansions and that their low frequency statistics connects to prime number theory. A link between Riemann hypothesis and 1/F noise arises in this context.

Technical analysis helps investors to better time their entry and exit from financial asset positions. This methodology relies solely on past information of the prices and volumes of financial assets to predict the future price trend of a financial asset. Modern research has established that combined with other sentiment measures such as social media, it can outperform the standard buy and hold strategy. Moreover, it has been documented that novice and professional investors apply technical analysis in their investing strategy. An experienced investor should combine fundamental analysis and technical analysis for better trading results. Programmers use technical analysis to create algorithmic trading systems that learns and adopts to the changing trading environments and performs trading accordingly without human involvement. There are hundreds of technical tools offered by known trading platforms. Investors must use specific tools that fits his trading style and risk adoption. Moreover, different financial assets such as stocks, ETFs, cryptocurrency, futures, and commodities demand different set of tools. Furthermore, investors should use these tools according to the time frame they use for trading. This chapter will discuss different technical tools that are used to help traders of different time frames and different financial assets to achieve better returns over the traditional buy and hold strategy.