Methods and apparatus are provided for performing measurement of reference signals in the proper subframes of a first radio access technology while operating in a second RAT. The piston assembly includes a sleeve and a concentric cylindrical body whose respective first and second end surface areas define a first effective area while the second end surface area of the cylindrical body defines a second effective area within the bore. The modularity of this approach facilitates the modification andor updating of a system component without affecting the operation of other components.