CRYOGENIC TREATMENT DEVICE ENCODER

A treatment system for treating tissue is disclosed in which a handle with an elongate shaft projecting from the handle, a sheath axially slidable relative to the elongate shaft, and an electrode mounted on a proximal portion of the sheath is provided. A substrate having an elongate portion may be located within the handle. A plurality of first and second capacitive sensors may be positioned along the elongate portion. The electrode may be configured to slide along the elongate portion during movement of the sheath. The electrode may maintain contact with at least one of the first capacitive sensors at least one of the second capacitive sensors during movement of the sheath. The substrate may be configured to determine an axial position of the electrode based on a coupling capacitance caused by an electrode overlapping one or more of the first capacitive sensors and one or more of the second capacitive sensors.