CFOA-Based New Structure of Fractional Order Inverse Filters

This paper presents a CFOA-based fractional order inverse filter (FOIF) structure. Proposed structure utilizes two current feedback operational amplifiers (CFOAs), two fractional capacitors (FCs) and two resistors to design FOIFs to realize fractional order inverse low pass (FOILP), fractional order inverse high pass (FOIHP) and fractional order inverse band pass (FOIBP) responses. The proposed configuration of FOIFs is simulated in PSPICE using AD844 type CFOAs. Stability analysis and MATLAB simulations are also carried out to authenticate the theoretical propositions.

Realization Approach for Sinusoidal Signal Generation and Circuit with Easy Control

A new approach for realizing sinusoidal signal with quadrature property is proposed, which employs simple analog building blocks and facilitates easy tuning of the oscillation frequency, through a gain factor. The proposed approach is used for realizing a novel quadrature oscillator circuit, which requires three current feedback operational amplifiers and passive components. The proposed circuit provides outputs at low impedance terminals, and benefits from easy control over the frequency of oscillation (FO), which depends on resistive ratio, rather than absolute resistor values. The frequency control is also independent of the condition of oscillation (CO). The nonideal effects and the parasitic studies are presented. The verification of the proposed realization scheme for quadrature oscillators and the new circuit is carried out through both simulation studies and experimental results, using the commercially available chips.

Experimental Verification of Fractional-Order Filters Using a Reconfigurable Fractional-Order Impedance Emulator

Fractional-order filter design examples, realized through the substitution of fractional-order capacitors and inductors by a re-configurable active emulator, are presented in this paper. The implementation of the emulator is achieved using Current Feedback Operational Amplifiers (CFOAs) as active elements with the required fractional-order differentiation/integration performed through the employment of an integer-order multi-feedback topology. An important benefit, from the design flexibility point of view, is that the same topology could be re-configured for emulating both fractional-order capacitors and inductors through the appropriate selection of the time-constants and gain factors. The behavior of the realized filters is experimentally evaluated using commercially available CFOAs.

A Novel Floating Memristor Emulator with Minimal Components

A new floating emulator for the flux-controlled memristor is introduced in this paper. The proposed emulator circuit is very simple and consists of only two current feedback operational amplifiers (CFOAs), two analog multipliers, three resistors, and two capacitors. The emulator can be configured as an incremental or decremental type memristor by using an additional switch. The mathematical model of the emulator is derived to characterize its behavior. The hysteresis behavior of the emulator is discussed in detail, showing that the pinched hysteresis loops in v-i plane depend not only on the amplitude-to-frequency ratio of the exciting signal but also on the time constant of the emulator circuit itself. Experimental tests are provided to validate the emulator’s workability.

Commercially Available Active Device Based Grounded Inductor Simulator and Universal Filter with Improved Low Frequency Performances

In this paper, a new grounded inductor simulator employing two current feedback operational amplifiers (CFOAs), three resistors and one grounded capacitor which is suitable for IC fabrication is proposed. Also, a new voltage-mode (VM) universal filter with three input and single output is given as application example of the grounded inductor simulator. The universal filter with low output impedance can be easily cascaded with other VM circuits. Both of the proposed circuits have the feature of improved low frequency performances, and can be easily constructed by two commercially available active devices such as AD844s. However, both inductor simulator and universal filter need a single passive component matching condition. Simulation and experimental test results are given to demonstrate the performance and workability of the proposed grounded inductor simulator and filter structure.