Patent ID: 8841899
Filing Date: 2014-09-23
Classification: G01V

Abstract:
1. An electro-magnetic tomography apparatus, comprising: a modulator configured to modulate a reference signal using a pseudo-noise signal to thereby generate a modulated signal; a transmitter configured to transmit the modulated signal; a receiver configured to receive the modulated signal transmitted from a transmitter; an amplitude detector configured to compare an amplitude magnitude of the modulated signal received by the receiver and that of the reference signal to thereby obtain a received amplitude; and a demodulator configured to demodulate the modulated signal received by the receiver using the pseudo-noise signal to thereby generate a cyclic signal, compare a phase of the reference signal and that of the cyclic signal to thereby measure the phase of the cyclic signal, and determine a phase of the received modulated signal based on the measured phase of the cyclic signal, wherein the pseudo-noise signal has a frequency that is lower than all frequencies of the reference signal, and a wavelength that is longer than a distance between the transmitter and the receiver.