Methods, Devices And Systems Which Determine A Parameter Value Of An Object Or An Environment From A Voltage Reading Associated With A Common Mode Signal Of A Balanced Circuit

Abstract

A method for determining a value of a parameter of an object or an environment includes positioning a device having a balanced circuit in or on an object or within a particular environment, wherein the balanced circuit comprises elements which are operationally sensitive to changes in a parameter of the object or the environment. The method further includes measuring a common mode signal of the balanced circuit and determining, from the common mode signal, a value of the parameter. An exemplary implementation of the method includes determining temperature using a resistive sensor having a Wheatstone bridge circuit with two variable resistors and two fixed resistors. Embodiments of systems and devices configured to employ such methods are provided, particularly medical probes, electronic signal monitoring devices, and systems employing such devices.

What is claimed is: 
     
         1 . A method for determining values of parameters of an object or an environment, wherein the method comprises:
 positioning a device in or on an object or within a particular environment, wherein the device comprises a balanced circuit, and wherein the balanced circuit comprises elements which are operationally sensitive to changes in a first parameter of the object or the environment;   measuring a common mode voltage derived from the balanced circuit which correlates to a common mode signal of the balanced circuit;   determining, from the measured common mode voltage, a value of the first parameter;   measuring a differential voltage between signal output nodes of the balanced circuit; and   determining, from the differential voltage, a value of a second parameter of the object or environment which is different from the first parameter, wherein at least one of the steps of measuring the differential voltage and determining the value of the second parameter is performed substantially simultaneously with at least one of the step of measuring the common mode voltage and determining the value of the first parameter.   
     
     
         2 . The method of  claim 1 , wherein the first and second parameters are selected from a group consisting of temperature, pressure, volume, velocity, pH, oxygen concentration and humidity. 
     
     
         3 . The method of  claim 1 , wherein the balanced circuit is a half-bridge Wheatstone bridge circuit. 
     
     
         4 . The method of  claim 3 , wherein half-bridge Wheatstone bridge circuit comprises two variable resistors respectively comprising opposing sides of the Wheatstone bridge circuit. 
     
     
         5 . The method of  claim 1 , wherein the device is a medical probe. 
     
     
         6 . A system, comprising:
 a device having a balanced circuit;   an electronic signal monitoring unit configured for electrical communication with the device to measure electrical parameters of the balanced circuit;   circuitry for coupling to the balanced circuit, wherein the circuitry, when coupled to the balanced circuit, is configured to:
 generate a common mode voltage which correlates to a common mode signal of the balanced circuit; and 
 generate a differential voltage of the balanced circuit, wherein the electronic signal monitoring unit comprises means for measuring the differential voltage and the common mode voltage; and 
   a storage medium comprising program instructions which are executable by a processor for respectively determining, from the common mode voltage and the differential voltage, different parameters of an environment in which the device is arranged.   
     
     
         7 . The system of  claim 6 , wherein the different parameters are selected from a group consisting of temperature, pressure, volume, velocity, pH, oxygen concentration and humidity. 
     
     
         8 . The system of  claim 6 , wherein one of the different parameters is temperature, and wherein the device is absent a temperature sensor distinct from the balanced circuit. 
     
     
         9 . The system of  claim 6 , wherein the circuitry is disposed between the device and the electronic signal monitoring unit. 
     
     
         10 . The system of  claim 6 , wherein the circuitry is disposed within the device. 
     
     
         11 . The system of  claim 6 , wherein the circuitry is disposed within the electronic signal monitoring unit. 
     
     
         12 . The system of  claim 6 , wherein the device is a medical probe. 
     
     
         13 . The system of  claim 6 , wherein the balanced circuit is a half-bridge Wheatstone bridge circuit. 
     
     
         14 . A device, comprising:
 a Wheatstone bridge circuit having two fixed resistors and two variable resistors;   compensation circuitry coupled to the Wheatstone bridge circuit which is configured to compensate for variations of a resistive coefficient of a conductive material comprising the Wheatstone bridge circuit due to ambient temperature changes of the conductive material; and   common mode signal circuitry coupled to the Wheatstone bridge circuit which generates a voltage correlating to a common mode signal of the Wheatstone bridge circuit.   
     
     
         15 . The device of  claim 14 , wherein the compensation circuitry comprises one or more fixed resistors in parallel with at least one of the two variable resistors of the Wheatstone bridge circuit. 
     
     
         16 . The device of  claim 14 , wherein the device is a medical probe. 
     
     
         17 . The device of  claim 16 , wherein the common mode signal circuitry is disposed within an electrical connector of the medical probe. 
     
     
         18 . The device of  claim 16 , wherein the common mode signal circuitry is disposed within a tip of the medical probe. 
     
     
         19 . The device of  claim 16 , wherein the medical probe is a catheter. 
     
     
         20 . The device of  claim 14 , further comprising reference voltage circuitry for generating a biased reference voltage relative to an excitation voltage applied to the Wheatstone bridge circuit.