Test data generator for generating test data patterns for the testing of a circuit having a frequency multiplication circuit, which increases a low clock frequency of an input clock signal received by a test unit with a specific clock frequency multiplication factor. The present disclosure also discloses new methods of making an introducer sheath with an inner liner for percutaneous insertion of a medical device into a patient. The transformed height data is created which describes the contents of a transformation in the form of height data, and the transformed height data is combined with the initial height bump map data to create the modified height bump map data. An interlock assembly can be provided to prevent closing of the vehicle closure member when the step member is in the deployed position. The invention also relates to corresponding systems and apparatuses.