Operation Amplifier Magnitude Response Degradation and Its Correction

Some biquad filters structures are characterized by a decreasing of the attenuation at high frequencies. Selected basic structures of biquads are compared with a view to the decrease of the attenuation over the transient frequency of the operational amplifier. Possible solution of higher-order filter described problem is to replace the biquad with an another biquad, that does not have this disadvantage. There are two variants: design with recalculation and/or direct design.