Background: This article describes the circuit construction of the sinusoidal quadrature
oscillator using two Voltage Differencing Gain Amplifiers (VDGAs) as active devices.
Methods: Since the presented oscillator circuit uses only two external grounded capacitors as passive
elements, it is quite suitable for monolithic integration point of view. The condition of oscillation
and the frequency of oscillation are non-interactive, and can be controlled electronically by tuning
two separate biasing currents. Non-ideal analysis and sensitivity performance are also discussed.
Results: The feasibility of the designed oscillator is justified by the PSPICE simulation results based
on TSMC 0.35-µm CMOS process parameters.
Conclusion: The effects of the VDGA non-idealities on the proposed circuit are also provided, and
the computer simulations based on TSMC 0.35-mm CMOS model parameters are included to evaluate
the performance of the circuit.