Wireless communication of physiological variables

1 . A system for measuring a physiological variable in a body, which system comprises:

a sensor ( 314 ) arranged to be disposed in the body for measuring the physiological variable and to provide a signal representing the measured physiological variable;

a control unit ( 322 ) arranged to be disposed outside the body; and

a wired connection ( 311 ) between the sensor and the control unit to provide a supply voltage from the control unit to the sensor, and to communicate said signal from the sensor to the control unit,

wherein the control unit has a modulator ( 301 ) for modulating a carrier signal with the received signal representing the measured physiological variable and a communication interface ( 401 , 701 ) for wireless communication of the modulated signal.

2 . The system according to claim 1 , further comprising:

a monitoring device ( 309 ) arranged to communicate via the wireless communication interface ( 401 , 701 ), to demodulate ( 313 ) the modulated signal which is wirelessly received via the communication interface, and to provide a representation of the measured physiological variable.

3 . The system according to claim 2 , wherein the monitoring device ( 309 ) is arranged to communicate via the wireless communication interface ( 401 , 701 ), to demodulate ( 313 ) a number of modulated signals wirelessly received via the communication interface from a number of control units ( 322 ), and to provide a representation of the measured physiological variables that correspond to the received modulated signals.

4 . The system according to claim 3 , wherein the modulated signals wirelessly received via the communication interface from a number of control units ( 322 ) is provided with an identifier such that each control unit may be identified by means of its modulated signal.

5 . The system according to claim 2 , wherein the monitoring device ( 309 ) is further arranged to supply the control unit with a supply voltage and control data via the communication interface ( 401 , 701 ).

6 . The system according to claim 1 , wherein the control unit ( 322 ) is arranged such that it may be powered via a power supply interface.

7 . The system according to claim 6 , further comprising:

a power source ( 316 ) arranged at the control unit ( 322 ) to provide the control unit with a supply voltage via the power supply interface.

8 . The system according to claim 5 , further comprising:

a switch ( 318 ) arranged to selectively provide the control unit with a supply voltage from the communication interface ( 401 , 701 ) or the power supply interface.

9 . The system according to claim 1 , wherein the radio frequency interface ( 330 , 340 ) of the control unit ( 322 ) is arranged such that communication is performed by means of inductive coupling between the control unit and a device ( 309 ) with which it is communicating via the communication interface.

10 . The system according to claim 9 , wherein the radio frequency interface of the control unit ( 322 ) is arranged such that communication of the control unit supply voltage is performed by means of inductive coupling ( 330 ) between the control unit and the device ( 309 ) with which it is communicating via the communication interface.

11 . The system according to claim 9 , wherein the radio frequency interface of the control unit ( 322 ) is arranged such that communication of the measured physiological variables and the control data is performed by means of capacitive coupling ( 340 ) between the control unit and the device ( 309 ) with which it is communicating via the communication interface.

12 . The system according to claim 1 , wherein the radio frequency interface of the control unit ( 322 ) is arranged such that communication is performed by means of capacitive coupling ( 401 , 701 ) between the control unit and a device ( 309 ) with which it is communicating via the communication interface.

13 . The system according to claim 1 , wherein the wired connection comprises a guide wire ( 311 ) arranged to position the sensor ( 314 ) within the body.

14 . The system according to claim 13 , wherein a core wire ( 119 ) of the guide wire ( 311 ) constitutes a first electric pole, and an outer tube ( 111 ) of the guide wire constitutes a second electric pole.

15 . A method of measuring a physiological variable in a body, which method comprises the steps of:

measuring the physiological variable by means of a sensor ( 314 ) arranged to be disposed in the body;

communicating, via a wired connection ( 311 ), a signal representing the measured physiological variable from the sensor to a position outside the body;

supplying, via the wired connection, the sensor with a supply voltage;

modulating ( 301 ), at the position outside the body, a carrier signal with the signal that represents the measured physiological variable; and

sending ( 701 ) the modulated signal wirelessly to a remote position.

16 . The method according to claim 15 , further comprising the steps of:

receiving the modulated signal at the remote position;

demodulating ( 313 ) the received modulated signal; and

providing a representation of the measured physiological variable for further use.

17 . The method according to claim 15 , wherein said position outside the body comprises a control unit ( 322 ) arranged with a wireless interface ( 401 , 701 ).

18 . The method according to claim 17 , further comprising the steps of:

wirelessly supplying, from the remote position, the control unit ( 322 ) with a supply voltage and control data.

19 . The method according to claim 17 , further comprising the step of:

supplying, via a power supply interface, the control unit with a supply voltage ( 316 ).

20 . The method according to claim 18 , further comprising the step of:

selectively supplying, via a switch ( 318 ), the control unit ( 322 ) with a supply voltage from the wireless communication interface ( 401 ) or the power supply interface.