Impedance determination
First Claim
Patent Images
1. An apparatus for use in performing impedance measurements on a subject, wherein the apparatus includes a processing system for:
- a) causing a first signal to be applied to the subject, the first signal being voltage drive signals to be applied to the subject via first electrodesb) determining sensed current signals caused by the voltage drive signals;
c) determining an indication of a second signal measured across the subject, the indication of the second signal being a body centre voltage derived from sensed voltages measured via respective second electrodes;
d) using the indication of the second signal to determine if an unacceptable imbalance exists; and
,e) if an unacceptable imbalance exists;
i) determining a modified first signal in accordance with the imbalance by;
determining upper and lower impedances for the subject using the sensed current signals, the voltage drive signals, and the body centre voltage; and
determining modified voltage drive signals using the upper and lower impedances and an ideal current signal indication; and
,ii) causing the modified first signal to be applied to the subject to thereby allow at least one impedance measurement to be performed.
1 Assignment
0 Petitions
Accused Products
Abstract
Apparatus for use in performing impedance measurements on a subject. The apparatus includes a processing system for causing a first signal to be applied to the subject, determining an indication of a second signal measured across the subject, using the indication of the second signal to determine any imbalance and if an imbalance exists, determining a modified first signal in accordance with the imbalance and causing the modified first signal to be applied to the subject to thereby allow at least one impedance measurement to be performed.
218 Citations
45 Claims
-
1. An apparatus for use in performing impedance measurements on a subject, wherein the apparatus includes a processing system for:
-
a) causing a first signal to be applied to the subject, the first signal being voltage drive signals to be applied to the subject via first electrodes b) determining sensed current signals caused by the voltage drive signals; c) determining an indication of a second signal measured across the subject, the indication of the second signal being a body centre voltage derived from sensed voltages measured via respective second electrodes; d) using the indication of the second signal to determine if an unacceptable imbalance exists; and
,e) if an unacceptable imbalance exists; i) determining a modified first signal in accordance with the imbalance by; determining upper and lower impedances for the subject using the sensed current signals, the voltage drive signals, and the body centre voltage; and determining modified voltage drive signals using the upper and lower impedances and an ideal current signal indication; and
,ii) causing the modified first signal to be applied to the subject to thereby allow at least one impedance measurement to be performed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
-
-
45. A method for use in performing impedance measurements on a subject, wherein the method includes, in a processing system:
-
a) causing a first signal to be applied to the subject, the first signal being voltage drive signals to be applied to the subject via first electrodes b) determining sensed current signals caused by the voltage drive signals; c) determining an indication of a second signal measured across the subject, the indication of the second signal being a body centre voltage derived from sensed voltages measured via respective second electrodes; d) using the indication of the second signal to determine any imbalance; and
,e) if an unacceptable imbalance exists; i) determining a modified first signal in accordance with the imbalance by; determining upper and lower impedances for the subject using the sensed current signals, the voltage drive signals, and the body centre voltage; and determining modified voltage drive signals using the upper and lower impedances and an ideal current signal indication; and
,ii) causing the modified first signal to be applied to the subject to thereby allow at least one impedance measurement to be performed.
-
Specification