Patent ID: 8102266

Claim:
A radio intra-subject information acquiring system comprising: a body-insertable apparatus that is inserted into a subject, the body-insertable apparatus including, a receiving resonance circuit formed with a variable capacitor and a receiving coil, and a capacitance controller that changes a capacitance of the variable capacitor so as to decrease a frequency difference between a resonance frequency of the receiving resonance circuit and a frequency of a radio signal received; and a transmitting and receiving apparatus that is disposed at the outside of the subject, and performs radio communications with the body-insertable apparatus, the transmitting and receiving apparatus including, a frequency variable oscillator that prescribes an oscillation frequency of a transmitted radio signal, and can adjust the oscillation frequency, a transmitting resonance circuit formed with a fixed capacitor and a transmitting coil, and a frequency controller that controls the frequency variable oscillator so as to decrease a frequency difference between the oscillation frequency and a resonance frequency of the transmitting resonance circuit that changes according to a change in a self inductance value of the transmitting coil.