Method and relative device for sensing amplitude and phase of an electrical signal

摘要

A method of sensing an amplitude and a phase of a varying electrical signal representing an impedance of an electrically conductive tissue through which an AC stimulation current is forced may include measuring a first amplitude value of the varying electrical signal corresponding to an arbitrary initial phase offset value and assuming the first amplitude value corresponds to the amplitude and assuming the arbitrary initial phase offset value corresponds to the phase. The method may include measuring a second amplitude value of the varying electrical signal at a phase offset different from the phase. The method may further include comparing the second amplitude value with the amplitude, and updating the amplitude and the phase to correspond to one of a maximum and a minimum amplitude value and to a corresponding phase offset.

主权项

1. A method of sensing an impedance of an electrically conductive tissue through which an AC stimulation current is forced, comprising:
taking a first sample of a varying electrical signal representing the impedance based upon an arbitrary initial phase offset with respect to a null phase of the AC stimulation current and assuming the first sampled value as a real amplitude of a modulating signal and the arbitrary initial phase offset as a real phase; taking at least one second sample of the varying electrical signal at a phase offset different from the assumed real phase; and comparing the at least one second sample with the assumed real amplitude, and updating at each period the assumed real amplitude and assumed real phase such as to correspond either to a maximum or minimum sample corresponding phase offset; and when the AC stimulation current is forced through a portion of tissue between voltage sensing electrodes, generating the varying electrical signal by
changing a phase of an AC voltage with respect to the AC stimulation current by the phase offset,calculating a product between the AC voltage and a voltage of the voltage sensing electrodes applied on a tissue,generating a replica of the product, andlow-pass filtering the replica.