Patent ID: 7523756

Claim:
A system comprising: a device that is adapted to be swallowed and passed through a subject, and includes a magnetic field generator generating a constant magnetic field; and a position transducer that includes: a magnetic detector detecting an intensity of a magnetic field component in a vertical direction, the magnetic field component being a component of the constant magnetic field generated by the magnetic field generator; and a position processor calculating a position of the device in the subject based on the intensity detected by the magnetic detector; wherein the device further includes: a predetermined function executing unit that obtains information of an inside of the subject; and a radio transmitting unit that transmits the information of the inside of the subject with radio communication, and the position transducer further includes a receiving unit that receives a radio signal transmitted from the radio transmitting unit; wherein the position transducer includes a plurality of receiving units each receiving a radio signal transmitted from the radio transmitting unit, and a selector that selects a receiving unit used for receiving a radio signal based on the position calculated by the position processor.