A dynamically selectable resistor network is provided in a star configuration for producing a weighted sum of input values, without attenuation from near zero contributions. Each branch of the star connected network comprises sets of impedance components, preferably resistors, that are actively selectable to produce permutated combinations of effective weighting values. The resistors code digital control bits and the outputs of sets of resistors in respective branches that correspond to the least significant control bits provide their outputs to the summing output node independently of the sets of resistors corresponding to control bits of other significance.