High Frequency CCII Based Proposed All-Pass Filter and quadrature oscillator

In this paper, a new circuit topology for realizing first-order all-pass filter based on a grounding capacitance multiplier is presented. This strategy presents a good solution to resolve the problems occurred by the integration of high capacitance value. And he give the possibly to realize a tuneable capacity by simple action on their bias current. Implementations of these topologies based on a based translinear CCII were done. The grounding capacitance multiplier has a tunable value in the range of [18.3pF-83.8pF] by varying a DC current between 10μA and 300μA. The proposed filter has high input and low output impedances, which make it suitable for cascading. As application examples, the proposed all-pass filter is used in realizing a quadrature oscillator. The quadrature oscillator has a tunable frequency in the range of [490MHz-595MHz]. The proposed filter and oscillator circuits are simulated using the SPICE simulation program to confirm the theory. Keywordsfirst-order all-pass filter, translinear Current conveyor, grounding capacitance multiplier, quadrature oscillator