An integrated circuit can be made more secure by programming a one time programmable circuit so that different signals are provided on terminals as compared to when the integrated circuit was not secure. The harmonic producing circuit superimposes a harmonic of an FM signal on the FM signal, and the harmonic phase shifting circuit shifts the phase of the harmonic. The substantially flat, flexible strap 14 is threaded through the curved elongated slot 16. The coil is wound on the magnetic center pole.