CDBA-based sinusoidal quadrature oscillator with current controlled amplitude

This paper describes a sinusoidal quadrature oscillator circuit using current differencing buffered amplifiers (CDBAs), that features a single-resistance-controlled frequency and current amplitude control. The proposed circuit contains two CDBAs, three resistors, and two grounded capacitors. The oscillation condition (OC) and the oscillation frequency (ω_o) of the circuit are independently controlled by a single resistor, whereas the oscillation amplitude is electronically controlled by an external DC current. Outputs of two sinusoidal voltages are shifted by 90°. The validity of the proposed circuit has been verified by hardware circuit tests using AD844 based CDBA.