THEORETICAL AND APPLIED ELECTRICAL ENGINEERING VOLUME: 14 | NUMBER: 2 | 2016 | JUNE VDCC Based Dual-Mode Quadrature Sinusoidal Oscillator with Outputs at Appropriate Impedance Levels Mayank SRIVASTAVA 1 , Dinesh PRASAD 2 1 Department of Electrical, Electronics and Communication Engineering, The Northcap University, HUDA Sector-23 A, 122017 Gurgaon, India 2 Department of Electronics and Communication Engineering, Faculty of Engineering and Technology, Jamia Millia Islamia, 110025 New Delhi, India mayank2780@gmail.com, dprasad@jmi.ac.in DOI: 10.15598/aeee.v14i2.1611 Abstract. This article presents a new dual-mode (i.e. both current-mode and voltage-mode) quadra- ture sinusoidal oscillator using two Voltage Differenc- ing Current Conveyors (VDCCs), two resistors and two capacitors. The proposed configuration use only grounded passive elements and enjoys independent re- sistor/electronic tuning of both Condition of Oscilla- tion (CO) as well as Frequency of Oscillation (FO). The quadrature current and voltage mode outputs of this circuit are available at appropriate impedance ter- minals. The behavior of presented oscillator is also ex- amined under non ideal/parasitic conditions. The va- lidity of the proposed configuration has been confirmed by SPICE simulations with TSMC 0.18 μm process pa- rameters. Keywords Dual-mode oscillator, electronic control, high impedance CM outputs, low impedance VM out- put, VDCC. 1. Introduction Oscillator is an important circuit configuration, which finds several applications in measurement, signal pro- cessing, communication, instrumentation and control systems [1], [2], [3], [4], [5]. A quadrature sinusoidal os- cillator which provides two 900 phase shifted sinusoidal outputs simultaneously is widely used in telecommu- nication engineering applications such as in quadra- ture mixers, single sideband modulators and direct- conversion receivers or for measurement purpose in se- lective voltmeters and vector generators [6], [7], [8]. Several VM and CM quadrature sinusoidal oscillators employing different Active Building Blocks (ABBs) have been reported in open literature. Careful investi- gation of literature available on quadrature oscillators reveals that most of the oscillators provide either volt- age mode quadrature outputs or current mode quadra- ture outputs but only very few circuits are those which provide voltage mode and current mode quadrature outputs simultaneously. This simultaneous availabil- ity of quadrature outputs is very useful in mixed mode applications where current and voltage signals are re- quired together. The earlier work on dual-mode quadrature sinusoidal Oscillators employing different active element(s) has been reported in [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21]. Unfortunately, these reported circuits suffer from one or more of following drawbacks: (i) presence of floating passive component(s), which is not desirable from the viewpoint of monolithic integra- tion (ii) lack of independent electronic control of both FO and CO (iii) lack of independent resistive control of both FO and CO (iv) non-availability of quadrature VM outputs at low impedance terminals (which need additional voltage followers for cascading) and (v) non- availability of high impedance explicit quadrature CM outputs (which need additional current followers for sensing and taking out the currents) (vi) use of ABB with current copy terminal(s) to get explicit CM out- puts (which need additional MOSFETs/BJTs to realize current copy terminal(s). Therefore, the purpose of this article is to present a new CM/VM sinusoidal quadrature oscillator employ- ing two VDCCs, two resistors and two capacitors which enjoys following advantageous features simultaneously c  2016 ADVANCES IN ELECTRICAL AND ELECTRONIC ENGINEERING 168