Multifunction Current Differencing Cascaded Transconductance Amplifier (MCDCTA) and Its Application to Current-Mode Multiphase Sinusoidal Oscillator

Abstract

In this study, a new versatile active element, namely multifunction current differencing cascaded transconductance amplifier (MCDCTA), is proposed. This device which adopts a simple configuration enjoys the performances of low-voltage, low-input and high-output impedance, wide bandwidth etc. It simplifies the design of the current-mode analog signal processing circuit greatly, especially the design of high-order filter and oscillator circuits. Moreover, an example as a new current-mode multiphase sinusoidal oscillator (MSO) using MCDCTA is described in this paper. The proposed oscillator, which employs only one MCDCTA and minimum grounded passive elements, is easy to be realized. It can provide random n ( n being odd or even) output current signals and these output currents are equally spaced in phase all at high output impedance terminals. Its oscillation condition and the oscillation frequency can be adjusted independently, linearly and electronically by controlling the bias currents of MCDCTA. The operation of the proposed oscillator has been testified through PSPICE simulation and experimental results.

Design and Experimental Evaluation of Quadrature Oscillator Employing Single FB–VDBA

“…As a result, many quadrature oscillator circuits have been reported in the literature [9][10][11][12][13][14][15][16][17] using different type of active elements. Designers of quadrature oscillators utilize various active elements such as multifunction current differencing cascaded transconductance amplifier [9], current differencing transconductance amplifier (CDTA) [10], operational amplifier [11], current differencing buffered amplifier (CDBA) [12], current feedback operational amplifier (CFOA) [13], differential difference current conveyor (DDCC) [14], current follower transconductance amplifier (CFTA) [15], fully differential current conveyor (FDCCII) [16], and double current controlled current feedback amplifier (DCC-CFA) [17].…”

“…Designers of quadrature oscillators utilize various active elements such as multifunction current differencing cascaded transconductance amplifier [9], current differencing transconductance amplifier (CDTA) [10], operational amplifier [11], current differencing buffered amplifier (CDBA) [12], current feedback operational amplifier (CFOA) [13], differential difference current conveyor (DDCC) [14], current follower transconductance amplifier (CFTA) [15], fully differential current conveyor (FDCCII) [16], and double current controlled current feedback amplifier (DCC-CFA) [17]. However, the oscillators mentioned above suffer from one or more disadvantages; -having two or three active elements [10][11][12][13][14][15]17] -consisting of high number of passive components [11][12][13][14]16] -not being suitable for voltage mode filter structure due to high output impedance [10,12,14,16] The purpose of this paper is to introduce a voltagemode quadrature oscillator, based on a single FB-VDBA.…”