Patent ID: 8204441

Claim:
A transmitting apparatus that has a capsule-shaped casing and transmits data, comprising: a receiving unit that receives an external specifying signal from the outside of the casing for specifying a center frequency of data to be transmitted; a control unit that outputs a specifying signal corresponding to the center frequency; a frequency switching circuit that includes a center frequency adjuster that adjusts a center frequency of a carrier wave that carries the data to be transmitted; a frequency modulator that modulates a frequency of the carrier wave according to the center frequency and the data to be transmitted; and a frequency switching unit, of which a variable capacitance unit is connected in parallel to an external resonance circuit that oscillates the carrier wave, that switches the center frequency of the carrier wave on the basis of the specifying signal; and a voltage control unit that controls voltage applied to the variable capacitance unit on the basis of the specifying signal to vary the capacitance and finely adjusts a resonance frequency of the external resonance circuit.