| 摘要 |
A marker of the electromagnetic resonance type is designed with a one-layer coil (6) on a ferrite core (4) having a length equal to half the length of a standard core, whereby two markers can be made out of one such standard length. The resulting short cores have a very good strength, whereby a surrounding protective housing (2) may be thin-walled, such that the entire marker may be produced with relatively small dimensions. The one-layer coil (6) conditions a high efficiency. The coil is produced as a self-carrying unit (6), which can be displaced along the core (4), and in the production the marker may be adjusted to the resonance frequency in a simple manner by displacing the coil unit until a maximum output signal is detected, whereafter the coil unit is fixed to the core in that particular position. |
