Low-sensitivity high-frequency tunable active filter without external capacitors

An active filter is discussed which uses only resistors and two operational amplifiers represented by their single-pole model, but no external capacitors. The filter has very low sensitivities to all circuit parameters, is tunable over exceptionally wide frequency ranges, and is suitable for high-frequency and medium- applications. The usable frequency range is limited only by the validity of the single-pole model of the amplifiers used. The circuit may be used both as a lowpass and as a bandpass. Extensive room-temperature experimental results are presented.