Memcapacitor and meminductor are two new nonlinear memory circuit components defined on the basis of memristor. In the absence of physical devices of memcapacitor and meminductor, applying their equivalent circuit models into actual circuits to explore the characteristics of memcapacitor- and meminductor-based nonlinear circuits is meaningful. In this paper, a nonlinear oscillating circuit is designed based on the given nonvolatile memcapacitor and meminductor models, whose memory characteristics are analyzed using POP method in detail, and a series of dynamic characteristics of the novel chaotic circuit are analyzed, including Poincare section, equilibrium point, system stability, bifurcation diagrams, Lyapunov exponent spectrums and dynamic map of the system. By analyzing the influence of parameters on system dynamics, the evolutionary law of the system is obtained, which helps to better use of this chaotic oscillator in possible application areas like communication encryption and synchronization approach dependent on the initial setting. In particular, coexisting attractors are found under different initial values, by drawing the attractive basin, four different types of attractors in the system are discovered, and from the attractive basin, the evolutionary process of the system under different initial values is obtained. Finally, the validity of the system is verified by DSP experiment, and the experimental results are consistent with the theoretical analysis.

Chaotic oscillator based on memcapacitor and meminductor

The nanoscale size and controllable memristance of Memristor (MR) have shown evident superiorities for structuring new integrated circuits with different functions. With regards to the reported MR based filters, their cut-off frequencies could be hardly hot-line controlled on purposes. In this paper, by using the boundary values of memristance, a method for hot-line adjusting cut-off frequencies is newly proposed by inputting a preset DC voltage together with the to-be-filtered signal, without the requirement of extra memristance write circuits, which is hence beneficial for integrated implementation. The floating MR emulator is firstly presented and the saturation operation of its memristance is interpreted. A family of MR based low-pass filters with controllable cut-off frequency are proposed by combining the connection nodes of a memristive circuit network Z with the op amp. Two circuits of the low-pass filter family are chosen for demonstration, and the cut-off frequency and passband gain are calculated. Square and sinusoidal voltage signals are used to test the performance of the proposed low-pass filter family. Both the simulation and experimental results show that the proposed filters can achieve cut-off frequency adjustment with good filtering performance.

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A Family of Binary Memristor-Based Low-Pass Filters with Controllable Cut-Off Frequency

In this present contribution, a simple chaotic oscillator based on a memcapacitor with only one equilibrium point is reported.
 The proposed oscillator consists of an inductor (only storage element) and a nonlinear active memcapacitor which is the key component responsible for the complex behaviors exhibited by the circuit. The resulting mathematical model is a simple jerk-type equation system that is easy to manipulate both analytically and numerically.
 The numerical results reveal the emergence of a plethora of phenomena such as period-doubling bifurcations, antimonotonicity, offset-boosting, and multistability giving rise to several kinds of coexisting attractors among which the coexistence of six stable states. The PSpice investigations confirm the real feasibility of the proposed circuit.
 The complexity of the phenomena and behaviors observed make the particularity of the proposed memcapacitor–inductor circuit and thus constitutes an enriching contribution in nonlinear dynamics.

Complex dynamical behaviors in a memcapacitor–inductor circuit

\nPurpose\nThe purpose of this paper is to design and construct an amplitude shift keying (ASK) modulator, which, using the digital binary modulating signal, controls a floating memristor emulator (MR) internally without the need for additional control circuits to achieve the ASK modulated wave.\n\n\nDesign/methodology/approach\nA binary digital unipolar signal to be modulated is converted by a pre-processor circuit into a suitable bipolar modulating direct current (DC) signal for the control of the MR state, using current conveyors the carrier signal’s amplitude is varied with the change in the memristance of the floating MR. A high pass filter is then used to remove the DC control signal (modulating signal) leaving only the modulated carrier signal.\n\n\nFindings\nThe results from the experiment and simulation are in agreement showed that the MR can be switched between two states and that a change in the carrier signals amplitude can be achieved by using an MR. Thus, showing that the circuit behavior is in line with the proposed theory and validating the said theory.\n\n\nOriginality/value\nIn this paper, the binary signal to be modulated is modified into a suitable control signal for the MR, thus the MR relies on the internal operation of the modulator circuit for the control of its memristance. An ASK modulation can then be achieved using a floating memristor without the need for additional circuits or signals to control its memristance.\n

An internally-controlled memristor-based amplitude shift keying modulator

Digital potentiometers are substantial components for the design of many mixed-signal electronic circuits and systems. Their capability to program resistance value almost instantly provides hardware designers an additional level of freedom. Unfortunately, this feature is limited to DC and lower frequencies, due to parasitic effects. Nowadays, memristors as continuously tunable resistors are becoming candidates for potentiometer successors. Memristors are two-terminal non-volatile devices which have less significant parasitic effects and a wide resistance range. The memristance value can be changed on the fly. Using nanotechnology, memristor implementation has a nanoscale footprint with nanosecond transition between resistive states. In this paper, we present a comparison between the frequency characteristics of digital potentiometers and the only commercially available memristors. Memristor parasitic effects dominate at higher frequencies which extends the bandwidth. In order to present the advantages of memristive circuits, we have analyzed and implemented tunable circuits such as a voltage divider, an inverting amplifier, a high-pass filter, and a phase shifter. A commercially available memristor by KnowM Inc. is used for this purpose. Experimental results obtained by the measurements verify that a memristor has equal or better characteristics than a digital potentiometer. Memristive realizations of voltage dividers and inverting amplifiers have a wider bandwidth, while filters and phase shifters with a memristor have almost identical frequency characteristics as the corresponding realizations with a digital potentiometer.

https://www.mdpi.com/2079-9292/10/2/181/pdf

Memristors as Candidates for Replacing Digital Potentiometers in Electric Circuits

The meminductor is a novel kind of electronic device with dynamic variable inductance. On account of its unique memory property, meminductor has garnered increasingly extensive interest from numerous researchers. However, as a nanoscale circuit element, meminductor has been facing huge challenges of variation control during the manufacture process. In this paper, three types of nonlinear meminductor models are described with constructive procedures. Meanwhile, the meminductive characteristics of these three models are verified based on a series of numerical simulations, respectively. In particular, according to the most realistic meminductor electro-mechanical model, we discuss its device characteristics influenced by parameter variation control in detail, i.e., length variation, coil area variation, coil variation and magnetic conductivity variation. Finally, the effectiveness and validity of the proposed scheme are verified by a number of computer simulations, which may contribute to providing theoretical references and reliable experiment basis for the further development of the manufacture of the meminductor and its application research.

The nonlinear meminductor models with its study on the device parameters variation

Based on the electrical properties of memristor, the spintronic memristor is introduced into analog circuit design. Through programming the memristor by pulse signals, a programmable memristor potentiometer is designed in this paper. The potentiometer has the advantages of simple structure, small volume and continuous variable dynamic range. Based on the potentiometer above, this paper presents an amplifier circuit whose magnification is precisely adjustable and an active memristor-filter whose cut-off frequency and phase are adjustable as well. The circuit is characterized with smaller size, higher integration and lower power consumption, and its correctness and feasibility are verified by SPICE simulation. The research in this paper will promote the application of memristor in analog circuit, in addition, the performance of programmable memristor-analog circuit is satisfactory, which provides a new way for the integrated circuit design in the future.

Ting Yang

Papers

The nonlinear meminductor models with its study on the device parameters variation

A Programmable Memristor Potentiometer and Its Application in the Filter Circuit