Operational transresistance amplifier-based multiphase sinusoidal oscillators

Multiphase sinusoidal oscillator circuits are presented which utilize operational transresistance amplifier (otra) as the active element. the first circuit produces n odd-phase oscillations of equal amplitudes and equally spaced in phase. the second circuit is capable of producing n odd- or even- phase oscillations equally spaced in phase. an alternative approach is discussed in the third circuit,which utilizes a single-phase tunable oscillator circuit which is used to inject signals into a phase shifter circuits. an automatic gain control (agc) circuit has been implemented for the second and third circuit. the circuits are simple to realize and have a low component count. pspice simulations have been given to verify the theoretical analysis. the experimental outcome corroborates the theoretical propositions and simulated results. © 2011 rajeshwari pandey et al.