A versatile active RC building block with inherent compensation for the finite bandwidth of the amplifier

An earlier paper by the authors describes an easily trimmed universal building block for active RC filters which possesses the valuable characteristic that, with suitable design, the Q -value can be made approximately independent of the gain-bandwidth product of the operational amplifiers. This makes the filter usable for high frequencies, while at the same time the dependence of the Q -value on temperature variations in the operational amplifiers is drastically reduced. Design formulas are presented, as well as comparative measurements which verify the theory. The building block is shown to have excellent characteristics both as a universal second-order building block and as a standard block for active ladder synthesis of bandpass filters.