Method for Interference Suppression in a Measuring Device
First Claim
1. A method for shielding an assembly of sensors that measures biomagnetic signals from external interferences, the assembly of sensors comprising at least one sensor, characterised in that the method comprises the steps of:
- providing the assembly of sensors with at least one magnetic feedback, wherein the difference signal of one feedback is obtained from at least one sensor of the aforementioned assembly of sensors;
producing in the region of the assembly of sensors a magnetic field that compensates for external interferences with at least one actuator disposed outside the assembly of sensors; and
the difference signal that produces a compensation voltage in the actuator is a linear combination of the signals of one or more sensors; and
using the SSS method to separate the biomagnetic useful signal being measured from the signals (originating from outside the measurement region), which signals are produced by the actuators and the external interferences.
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Abstract
The present invention describes a method enabling one to shield a device that measures weak biomagnetic signals from strong magnetic interference fields. The measurement sensors are provided with a feedback compensation loop, the difference signal of which is obtained from the measurement sensors themselves. As the actuator of the feedback function, one or more coils are responsible for eliminating, the external interference fields in the region of the sensors. Difference signals can be generated as a linear combination from the signals of two or more sensors. In the control logic, the SSS method can be used to numerically separate the biomagnetic signal being measured from the signals produced by the sources—compensation coils and interference sources—disposed outside the measurement region. The interference suppression can be enhanced by placing the assembly of sensors and the actuators within a magnetically shielding room.
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Citations
20 Claims
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1. A method for shielding an assembly of sensors that measures biomagnetic signals from external interferences, the assembly of sensors comprising at least one sensor, characterised in that the method comprises the steps of:
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providing the assembly of sensors with at least one magnetic feedback, wherein the difference signal of one feedback is obtained from at least one sensor of the aforementioned assembly of sensors; producing in the region of the assembly of sensors a magnetic field that compensates for external interferences with at least one actuator disposed outside the assembly of sensors; and
the difference signal that produces a compensation voltage in the actuator is a linear combination of the signals of one or more sensors; andusing the SSS method to separate the biomagnetic useful signal being measured from the signals (originating from outside the measurement region), which signals are produced by the actuators and the external interferences. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system for shielding an assembly of sensors measuring biomagnetic signals from external interferences, the system comprising:
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an assembly of sensors (10, 45) comprising at least one magnetic sensor; a feedback coil (14) coupled to each sensors; control electronics (11) controlling the measuring device; characterised in that the system further comprises; at least one magnetic feedback coupled to an assembly of sensors, wherein the difference signal of one feedback is obtained from at least one sensor (10, 45) of the aforementioned assembly of sensors; at least one actuator (12, 13, 42, 43) disposed outside the assembly of sensors for producing a magnetic field in the region of the assembly of sensors (10, 45), the magnetic field compensating for external interferences; and
the difference signal that produces a compensation voltage in the actuator is a linear combination of the signals of one or more sensors, (10, 45); andcontrol electronics (11) for separating the biomagnetic useful signal from, the signals (originating from outside the measurement region), which signals are produced by the actuators and the external interferences. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification