High Input Impedances Voltage-mode First-order Filters with Grounded Capacitors using CCIIs

Background: Three high input impedances voltage-mode first-order filters are presented. Methods: The first proposed circuit uses one multi-output second-generation current conveyor, two resistors and one grounded capacitor. The second proposed circuit uses two second-generation current conveyors, three resistors and one grounded capacitor. The third proposed circuit uses one multi-output second-generation current conveyor, one resistor and two grounded capacitors. Results: First-order lowpass and allpass filters can be simultaneously obtained in the first proposed circuit. First-order lowpass, highpass and allpass filters can be simultaneously obtained in the second proposed circuit. The third proposed circuit can realize first-order allpass filter. Conclusion: All the proposed circuits have the advantages of high input impedances and using only grounded capacitors.