Patent ID: 7002333

Claim:
PROCESS FOR COMPENSATING THE LOW FREQUENCY MAGNETIC FIELD IN AN INDUCTIVE SIGNAL COUPLING UNIT, wherein the coupling unit comprises a ferromagnetic core ( 30 ) which encloses a conductor through which a low frequency current ( 1 ) is circulating to inject a high frequency signal therein; characterised in that it comprises: a simultaneous obtaining and injecting of a compensating current by means of an independent ferromagnetic core ( 16 ) and a compensation winding ( 33 ) provided on the coupling unit which causes that in the inductive coupling unit a magnetic field is produced equal and opposite to that produced by the current circulating through the conductor ( 1 ), whereby saturation in the magnetic core of the inductive coupling unit is avoided, and an injecting of the compensating current through a low pass filter which offers high impedance to the high frequency signal desired and a compensation by means of at least one winding ( 19 ) with a radiofrequency choke ( 18 ) in series with the object that it offer a high impedance to a signal ( 2 ) which is injected through a signal winding ( 31 ).