A geometric ladder circuit produces a transfer function having
substantially uniform steps measured in dB. Where the ladder has a
plurality of substantially identical resistor rungs of a first
resistance, one stile that is a conductor connecting the rungs, and
another having a series of substantially identical resistors of a second
resistance, then for identical currents injected at different rungs, the
output signal at an end of the ladder is attenuated by a number of
substantially equal steps, one for each rung between input and output.
For a ladder with a base rung R, an output at an end opposite the base
rung, stile resistors of resistance .alpha.R, and other rungs all of
resistance (1+(1/.alpha.))R, the step size is 20 log.sub.10(1+.alpha.).