Comments on "A novel 'follow the master' filter"

The above work presents a technique for stabilizing the pole-frequency (ω
0
) 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 ω
0
is stabilized; therefore, most of the conclusions in the above letter are only approximately correct for the special case of a low ω
0
Q-product.