A system for repossessing a machine may include a transmitter configured to transmit a signal to the machine. In another embodiment, individual nailing flanges are manufactured and delivered on site, including a strip of tape secured to the nailing flange with an outer portion of the tape extending beyond the outer edge of the flange. A predetermined surface astigmatism is provided on the main meridian. The band may be a one-piece or two-or-three-piece assembly and may be formed of an suitable metallic or plastic material. A phase detector reference circuit determines from peak values of the analog signal at least two allowable levels of the analog signal including a reference-crossing level.