Reducing spread resistance in high Q state variable filters

In this paper we propose a method to reduce the resistance spread in the high Q realizations of the KHN and Tow-Thomas state variable filters. This resistance spread is reduced by noting that a single resistor controls the value of the pole Q, thus by substituting this resistor by a T of resistors it is possible to reduce the spread by up to a factor of 10. Simulations confirm the proposed technique.