Sensor system for measuring biopotentials

A system for measuring a biopotential signal produced by a body in free space, said system comprising:

• an electrode made of a conducting material, said electrode being positionable at a location adjacent the body to place said electrode at a first potential;
• a conductor located at a fixed distance from said electrode;
• a means for generating a reference potential;
• and
• a high impedance amplifier connected to said reference potential generating means, with said amplifier having an input port electrically connected to said electrode to compare said first electrical potential of said electrode with said reference potential to generate a signal indicative of the biopotential signal, and wherein said conductor is located to shield said electrode from electrical noise wherein said conductor is adapted to be interposed between said electrode and said body.

A system for measuring a biopotential signal at a location adjacent to a patient, said system comprising:

• means for generating a reference electrical potential;
• a probe having an electrode positionable at said location to place said electrode at a first electrical potential, a conductor spaced from said electrode, and a highimpedance amplifier positioned to interpose said conductor between said amplifier and said electrode, said amplifier electrically connected to said generating means and said electrode to compare said first electrical potential to said reference electrical potential and generate a signal that is indicative of the biopotential signal in response thereto;
• and
• means for controlling the electrical potential of said conductor to shield said electrode from electrical noise.

A method for measuring a biopotential signal at a location adjacent to a patient, said method comprising the steps of:

• providing an electrode made of a conductive material;
• maintaining a conductor spaced at a fixed distance from said electrode;
• controlling the electrical potential of said conductor to shield said electrode from electrical noise;
• coupling a high impedance amplifier to said electrode for movement therewith;
• positioning said electrode at said location to place said electrode at a first electrical potential;
• placing the conductor between the electrode and said high impedance amplifier;
• generating a reference electrical potential;
• inputting said first electrical potential and said reference electrical potential into said high impedance amplifier;
• and
• using said high impedance amplifier to compare said first electrical potential to said reference electrical potential and generate an output signal that is indicative of the biopotential signal in response thereto.

A probe for measuring a biopotential signal produced by a body in free space comprising:

• a first electrode made of a conducting material, the first electrode being adapted to be positioned adjacent the body to place the first electrode at a first potential;
• a first conductor spaced from the first electrode;
• system electronics for reviewing input from the first electrode located near the first electrode and separated from the first electrode by the first conductor;
• and
• a material having a relatively low electrical conductivity and dielectric constant interposed between the first conductor and the first electrode thus minimizing electrical coupling between the first conductor and the first electrode.