Propositions to widen the frequency bandwidth of an integrator
The transfer function, T, of an ideal integrator is 1/τs. Its phase, equal to −π/2, is independent of the frequency value, whereas the gain decreases in a proportional way with this value of ω. However, on the one hand, it is usually necessary to limit the DC gain so that the transfer function takes the shape T=k/(1+kτs). On the other hand, the active components such as operational amplifiers (op. amps.) or current feedback operational amplifiers are not perfect and they bring a supplementary pole at a high frequency. Therefore the bandwidth where the integrator phase is equal to −π/2 is included between ωMIN and ωMAX. For a couple DC gain and an op. amp. given, increasing the ratio ωMAX/ωMIN to a maximum is proposed.