Single CDCTA Based Electronically Adjustable Current-mode Quadrature Sinusoidal Oscillator

Abstract

The realization of the current-mode quadrature sinusoidal oscillator was presented in this paper. In this design, a single active building block, named Current Differencing Cascaded Transconductance Amplifier (CDCTA) was used with grounded resistor and two grounded capacitors. The proposed circuit was a simple structure which was attractive for integrated circuit implementation. The proposed oscillator could generate two sinusoidal signals with 90°degree phase difference. The output current nodes were high impedance which was ideal for cascading in the current-mode circuit without the requirement of the current buffers. Moreover, the control of the Frequency of Oscillation (FO) and the Condition of Oscillation (CO) were orthogonally and electronically via the DC bias current of CDCTA. The workability of the proposed sinusoidal oscillator was verified with PSpice in which simulation results agree well with theoretical expectations.