Comments on "A novel 'follow the master' filter"
J.R. Brand, Rolf Schaumann, K.R. Rao, A.T. Vernekar · Proceedings of the IEEE · 1978
The above work presents a technique for stabilizing the pole-frequency (ω0) of active R filters which is essentially identical to one reported earlier, but in which different conclusions are obtained concerning the technique's merits. Amplifier excess phase will generally cause pole-Q deviations with temperature even if ω0is stabilized; therefore, most of the conclusions in the above letter are only approximately correct for the special case of a low ω0Q-product.