Patent ID: 7869866

Claim:
A device for the measurement of body impedance comprising: means for injecting a test current through a first set of electrodes to the patient's body, including: at least one oscillator and at least one voltage—current converter and means to read voltage variations between two electrodes belonging to a second set of electrodes including: a demodulator; at least one filter; at least one differential amplifier with two outputs having opposite phase and at least one low pass filter, wherein said at least one oscillator is a sinewave oscillator and wherein said demodulator is a coherent demodulator further including at least one comparator and at least one switch, and wherein the output of said sinewave oscillator is connected to the input of said voltage-current converter, the output of said voltage-current converter is connected to said first set of electrodes, said second set of electrodes is connected to the input of said at least one filter, the output of said at least one filter is connected to the input of said at least one differential amplifier, the first output of said at least one differential amplifier is connected to a first input of said at least one switch, the second output of said at least one differential amplifier is connected to a second input of said at least one switch and to the input of said at least one comparator, the output of said at least one comparator is connected to the control input of said at least one switch, the output of said at least one switch is connected to the input of said at least one low pass filter.