Current-controlled quadrature oscillator using only CCCDBAs

An electronically tunable quadrature oscillator using only two current-controlled current differencing buffered amplifiers (CCCDBAs) and two grounded capacitors without external passive resistor is proposed. The outputs of two sinusoidal waveforms with 90° phase difference are available from the configuration. The oscillation condition and the oscillation frequency (¿
_o
) of the proposed oscillator circuit are tunable by electronically through controlling the external DC bias currents of the CCCDBAs. The simulation results with PSPICE are used to verify the theory.