A lettuce cultivar, designated Rio Bravo, is disclosed. According to one implementation, an apparatus includes multiple processing branches, each including: a continuous-time quantization-noise-shaping circuit, a samplingquantization circuit, and a digital bandpass filter. The position sensor is cooperated with the single guide shaft to inhibit rotation of the movable portion around the predetermined axis. The opposite leg of the spring extends through and rides in a partial annular groove in the bushing and acts on the blade as it is moved between the open and closed positions.