A third-order active-filter realization having a complex pole with a low-Q sensitivity with respect to the gain-bandwidth product of operational amplifier

A third-order state-variable filter realization using operational amplifliers is proposed to realize a high-Q high-frequency complex pole. This realization, under the optimal design condition, eliminates the effect of the gain-bandwidth product of the operational amplifier on the Q of the complex pole and ensures the stability. Hence high-Q high-frequency poles can be realized using this method.