Comments on "A novel \´follow the master\´ filter"

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.