CCTA Based Current-mode First Order Filter and Its Application in Quadrature Oscillator

This article presents a current-mode first order filter and application in quadrature oscillator circuit based on all-pass filter. The filter circuit using only single CCTA and single grounded capacitor. It is able to provide low-pass, high-pass and all-pass function. Morover, the proposed oscillator can provide two sinusoidal output currents with 90 degrees phase difference. The filter and oscillator circuits use only grounded capacitors without any external resistor and have high output impedance appropriate for cascade connection application in current mode which is capable to directly drive load. This qualification is very appropriate for further development into an integrated circuit. The results of PSPICE simulation program are corresponding to the theoretical analysis.

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W artykule przedstawiono prądowy filtr pierwszego rzędu i jego zastosowanie w generatorze kwadraturowym. Układ filtru wykorzystuje uziemiony kondensator i układ CCTA (current conveyor transconductance amplifier). Generator umożliwia wytwarzanie dwóch prądów sinusoidalnych przesuniętych w fazie o 90°.