| 摘要 |
The invention relates to a device and method for low-frequency magnetic fiel d compensation in an inductive signal coupling unit.According to the invention , the coupling unit comprises a ferromagnetic core (30) which surrounds a conductor through which a low-frequency current (1) flows, in order to injec t a high-frequency signal therein. The invention is characterised in that it consists in detecting the current (1) flowing through the conductor or the magnetic field (3) generated in the coupling unit, producing a supply curren t from the value obtained during the aforementioned detection process and injecting the supply current produced in the coupling unit via a low pass filter (9), in order to generate a magnetic field (4) that is equal, but in the opposite direction to that produced by the current (1) from the conducto r in the above-mentioned coupling unit, such as to prevent saturation of the magnetic core (30) without adding insertion losses. In general, the inventio n can be used for communication systems that require the injection of a radiofrequency signal in a conductor and, in particular, in systems using th e electrical network as a transmission means.
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