Resistor-less current-mode four-phase quadrature oscillator using CCCDTAs and grounded capacitors

A current-mode four-phase quadrature oscillator (FPQO) using 2 current controlled current differencing transconductance amplifiers (CCCDTAs) and 2 grounded capacitors is presented. The proposed oscillator can provide 4 sinusoidal output currents with 90 phase difference. The oscillation condition and oscillation frequency can be controlled independently and electronically by adjusting the bias currents of the CCCDTA. Both the oscillation condition and oscillation frequency tuning laws are non-interactive and dual-current controlled. High output impedances of the configuration enable the circuit to be cascaded without additional current buffers. The use of only grounded capacitors is ideal for integration. The circuit performances are depicted through PSPICE simulations, they show good agreement to theoretical anticipation.