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A New Mixed-Mode OTA-C Filter/Oscillator Circuit
Muhammad Taher Abuelma’atti and Abdulwahab Bentrcia

A new mixed-mode biquad circuit is presented. The circuit uses eight operational transconductance amplifiers (OTAs), two grounded capacitors and can realize inverting or non-inverting lowpass, highpass, bandpass, notch, lowpass notch, highpass notch and allpass responses from the same topology. The circuit can be driven by voltage or current and its output can be voltage or current. In addition to the single ended input/single ended output voltage-mode realizations, the circuit can also realize differential input/single ended output responses. The parameters ωo and ωoQo enjoy independent electronic tunability. The circuit can also realize a sinusoidaloscillator. The frequency and the condition of oscillation are electronically tunable and are totally uncoupled. Simulation results are included.

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