电流模式双二次滤波函数的AOA实现

为获得高精度电流模式双二次滤波器,以双VFA电压模式二阶通用滤波器为原型,用伴随网络的概念设计出AOA电流模式双二次滤波函数的新电路.通过改变输入信号的作用点,该电路可分别实现低通、带通和高通输出.该电路不仅具有电流模电路的特点,而且其无源灵敏度低,电路简单;品质因素、极点角频率取决于电容比值和电阻比值,从而可实现二者的独立、精确调节.计算机仿真与理论分析一致.

Realization of Biquadratic Filtering Function of a Current-mode-based on AOA

To obtain current-mode biquadratic filter with high accuracy,a voltage-mode second order universal filter based on two VFA's was transformed into a current-mode biquadratic filter-based on two AOA's by means of the concept of adjoint network.Functions,such as low-pass,band-pass,and high-pass filtering,can be realized by changing position of input signal.The circuit possesses many properties of current-mode circuit.Its sensitivity is lower,and its pole angular frequency and quality factor can be tuned accurately and independently,and the circuit is very easy in this process.Compute simulating results are consistent with theoretical analyses.