Patent ID: 7876859

Claim:
A management system of an object, the management system comprising: a reader/writer; and a semiconductor device which is provided to the object and capable of transmitting and receiving electromagnetic waves to/from the reader/writer, wherein the semiconductor device comprising: a resonant circuit for generating an alternating signal; a power source circuit for rectifying the alternating signal and generating a power source voltage and a ground voltage; a demodulation circuit for demodulating the alternating signal and generating a first demodulation signal; and a correction circuit for correcting the first demodulation signal and generating a second demodulation signal, wherein the first demodulation signal is a digital signal having a Low level potential and a High level potential, wherein the correction circuit corrects the first demodulation signal when the High level potential of the first demodulation signal becomes lower than the power source voltage or when the Low level potential of the first demodulation signal does not become as low as the ground voltage, and wherein an amplitude of the second demodulation signal is equal to an amplitude of the power source voltage.