Low-noise state-space realisation of bandpass active filter

An active 2nd-order bandpass state-space filter realisation known as the symmetric-form filter has been studied theoretically and practically and has been found to have desirable qualities, particularly those of low noise and good linearity. The noise and linearity performance of this realisation has been compared with that of the companion-form filter (feedforward filter).5.7 The dynamic range of the symmetric form, expressed as a power ratio, is shown to be 1000 times greater than that of the companion form having the same transfer function and using the same type of operational amplifier.