Adjustable Multiphase Sinusoidal Oscillator with Fractional–Order Elements

Abstract

This paper presents a fractional-order multiphase oscillator with adjustable FO (Frequency of Oscillation). The oscillator utilizes the following components: CCTA (Current Conveyor Transconductance Amplifier), OTA (Operational Transconductance Amplifier), auxiliary OTRA (Operational Transresistance Amplifier), two FOC (Fractional-Order Capacitors) and auxiliary resistors. The proposed structure provides three voltage outputs and their inverted variants for three selected values of α = 0.3, 0.5, and 0.8 of FOC. The FO is tuned by changing the values of the transconductances of the OTA and CCTA. The features of the presented circuit were verified by PSpice simulations with behavioural models of the active elements. Analysis of the dependence of the values of the transconductances on values of α and frequency is provided. A THD (Total Harmonic Distortion) and parasitic analysis of the circuit was also made.

On the performance of electronically tunable fractional-order oscillator using grounded resonator concept

“…These expectations are clear from (12). In fact, a specific selection of the order can help with the enlargement of the frequency adjustability range and with these issues in low-voltage designs [11], [15], [17] (limited range of driving voltage). In other words, variation of the order of power in the equation for the oscillation frequency has an effect on the available tunability range when the identical range of driving force is used.…”

“…in comparison to the topologically simplest solutions (for example [16]). Electronically tunable features of a multiphase sinusoidal fractional-order oscillator were studied and practically tested in [17] for the first time. However, as will be discussed later, some important features of this oscillator are not discussed.…”