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Electronically Tunable Quadrature Oscillator Using Current-Controlled Current Differencing Buffered Amplifiers
Worapong Tangsrirat and Wanlop Surakampontorn

A bipolar-based realization of a current-controlled current differencing buffered amplifier (CCCDBA) is introduced. It is then employed to realize an electronically tunable quadrature oscillator, which uses only three CCCDBAs and two grounded capacitors. The new proposed oscillator circuit produces two quadrature sinusoidal outputs with 90º phase difference, where the oscillation condition and the oscillation frequency can independently controllable by electronic means through linearly adjusting an external DC bias current. PSPICE simulation results that confirm the theoretical prediction are also given and discussed.

Keywords: Current differencing buffered amplifier (CDBA), quadrature oscillator, current-controlled circuit.

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