Patent ID: 8847769

Claim:
A signal detecting device for determining a difference signal for an electrical measurement of a vital parameter of a living being, comprising: a plurality of electrodes configured to contact the living being and provide electrode signals; and an electrode selecting device configured to select a pair of electrodes for determining the difference signal from the plurality of electrodes based on the electrode signals so that a difference signal suitable for measuring the vital parameter is derivable from the electrode signals of the selected electrodes; wherein the electrode selecting device is configured to: apply a reference signal to a first electrode from the plurality of electrodes, to detect an electrode signal at a second electrode from the plurality of electrodes, to decide, based on a signal strength of the electrode signal at the second electrode, whether the first electrode and the second electrode contact the living being sufficiently, and to select, responsive to a decision that the first electrode and the second electrode contact the living being sufficiently well, the first electrode and the second electrode as the pair of electrodes for determining the difference signal, or to mark the first electrode and the second electrode as candidate electrodes for the selection of the pair of electrodes for determining the difference signal.