In a wavelength selective switch according to the present invention, an isolator is disposed between a lens array and a first lens. The method includes dividing a set of initial training data, derived from returns from a burst of identical pulses, into a set of censored data and a set of uncensored data. The armrest adapter further includes a splined peg for coupling to a pivoting mechanism of an articulated chair. The ESP and canister are lowered on a tubing string into the casing. By removing the load from the feedback loop, the loop is stabilized with only a very small or no compensating capacitor, allowing the quiescent current of the buffer to be reduced and the settling time to be improved.