Voltage mode third order quadrature oscillators using OTRAs

Abstract

In this paper, the authors present two topologies of voltage mode third order quadrature oscillator circuit using operational transresistance amplifier (OTRA). The first circuit is based on low-pass filter and integrator combination, whereas the second one is high-pass filter and differentiator combination. Both the circuits utilize two OTRAs and three resistors and capacitors each. The frequency of oscillation and condition of oscillation can be adjusted independent of each other in both the circuits. The non-ideality analysis of the circuits are also included. The PSPICE simulation and experimental results verify the theoretical proposition.

New Realization of Quadrature Oscillator using OTRA

“…The proposed QO topology is shown in Figure 2. It uses an OTRA based second order high pass filter [32] …”

“…A careful observation suggests that all the reported third order QO designs are based on forming closed loop using combinations of lossy and/or lossless integrators. In this paper a new OTRA based third order QO is proposed that adapts the scheme of using second order high pass filter and a differentiator in a feedback loop [32].A comparative statement of the proposed structure with previously reported QO circuits is recorded in Table 1. It may be observed from the table that the available topologies-presented in [19] are realized using op-amps however, the constant gain-bandwidth product and lower slew rate of the op-amps limit their high frequency operations.…”

“…This has led a consistent research effort towards second order QO design using wide variety of active blocks, as is evident from vast literature available [2][3][4][5][6][7][8][9][10][11][12][13][14] .It is well known that higher order networks, provide better accuracy, frequency response and distortion performance [15][16][17] as compared to lower order circuits. Owing to this in recent past few third order QO designs [15], [16], [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] have been reported. Realizing sinusoidal oscillator using closed loop with positive feedback is a well-established method.…”

Quadrature Oscillator Design with Gm-C Structure

“…In the literature, there are many quadrature oscillators, which were designed with such active elements, as operational transresistance amplifiers [1], current feedback amplifiers [2], current differencing buffered amplifier [3,4], second generation current conveyor [5], current controlled current differencing buffered amplifier [6], current differencing transconductance amplifier [7], fully differential second generation current conveyor [8], fully balanced voltage differencing buffer amplifier [9]. Furthermore, surface acoustic wave oscillators [10] can be found.…”

“…Circuit realizations of the quadrature oscillators, given in [1], require some floating capacitors, which are not suitable for integrated circuit implementation. In [2][3][4][5][6][7], the operation requires at least two active elements and three passive components.…”