An apparatus for influencing and/or detecting magnetic particles in a field of view, which apparatus comprises: - a selection field signal generator unit and selection field elements for generating a magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength where the magnetization of the magnetic particles is not saturated and a second sub-zone having a higher magnetic field strength where the magnetization of the magnetic particles is saturated are formed in the field of view, - a drive field signal generator unit, a signal receiving unit and a drive-receiving coil, said drive-receiving coil being configured both for changing the position in space of the two sub-zones (52, 54) in the field of view by means of a magnetic drive field so that the magnetization of the magnetic material changes locally and for acquiring detection signals, which detection signals depend on the magnetization in the field of view, which magnetization is influenced by the change in the position in space of the first and second sub-zone (52, 54), the apparatus being characterized in that it comprises: - a bridge unit coupled between said drive field signal generator unit and said signal receiving unit, said bridge unit comprising - a first bridge sub-unit comprising a first inductive or capacitive coupling element, - a second bridge sub-unit comprising a second inductive or capacitive coupling element, - a third bridge sub-unit coupled in series with said first bridge sub-unit, said third bridge sub-unit comprising a measurement inductor, and - a fourth bridge sub-unit coupled in series with said second bridge sub-unit, said fourth bridge sub-unit comprising said drive-receiving coil, and - a coupling unit coupled between the drive field signal generator unit and the bridge unit for coupling into the bridge unit, wherein the signal receiving unit is coupled to a first output terminal arranged between the first and second bridge sub-units (410, 420) and a second output terminal arranged between the third and fourth bridge sub-units (430, 440). - a selection field signal generator unit and selection field elements for generating a magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength where the magnetization of the magnetic particles is not saturated and a second sub-zone having a higher magnetic field strength where the magnetization of the magnetic particles is saturated are formed in the field of view, - a drive field signal generator unit, a signal receiving unit and a drive-receiving coil, said drive-receiving coil being configured both for changing the position in space of the two sub-zones (52, 54) in the field of view by means of a magnetic drive field so that the magnetization of the magnetic material changes locally and for acquiring detection signals, which detection signals depend on the magnetization in the field of view, which magnetization is influenced by the change in the position in space of the first and second sub-zone (52, 54), the apparatus being characterized in that it comprises: - a bridge unit coupled between said drive field signal generator unit and said signal receiving unit, said bridge unit comprising - a first bridge sub-unit comprising a first inductive or capacitive coupling element, - a second bridge sub-unit comprising a second inductive or capacitive coupling element, - a third bridge sub-unit coupled in series with said first bridge sub-unit, said third bridge sub-unit comprising a measurement inductor, and - a fourth bridge sub-unit coupled in series with said second bridge sub-unit, said fourth bridge sub-unit comprising said drive-receiving coil, and - a first bridge sub-unit comprising a first inductive or capacitive coupling element, - a second bridge sub-unit comprising a second inductive or capacitive coupling element, - a third bridge sub-unit coupled in series with said first bridge sub-unit, said third bridge sub-unit comprising a measurement inductor, and - a fourth bridge sub-unit coupled in series with said second bridge sub-unit, said fourth bridge sub-unit comprising said drive-receiving coil, and - a coupling unit coupled between the drive field signal generator unit and the bridge unit for coupling into the bridge unit,