A vehicle armrest assembly includes an armrest, a ratchet mechanism having a linear ratchet plate that cooperates with a pawl locking assembly to permit vertical adjustment of the armrest. The effective modulation rate that a particular modem can use for each discrete tone can be monitored over time using a schedule of pilot tones transmitted from the modems on different tones at different times. Embodiments of the CMP conditioning apparatus include a housing configured to connect to the positioning arm, and one side of the housing having a concave gimbal surface. The fracture fluid is supplied to a desired location in the subterranean formation to form at least one fracture where the viscosity of the fracture fluid is maintained. A false depth pixel may be identified by comparing a confidence value associated with the false depth pixel with a particular threshold.