Patent ID: 7876149

Claim:
A harmonic quadrature demodulation apparatus, comprising: an input terminal for externally receiving an input focused signal; a harmonic phase estimation unit for estimating a second-order harmonic phase component (φ 2 ) of the input focused signal from the input focused signal; and a second-order harmonic detection unit for detecting a second-order harmonic component (b(n)) from the input focused signal using the second-order harmonic phase component, wherein the second-order harmonic detection unit comprises: an in-phase component extractor connected to the input terminal and configured to extract an in-phase component of the input focused signal transmitted from the input terminal, a quadrature component extractor connected to the input terminal and configured to extract a quadrature component of the input focused signal transmitted from the input terminal, a Hilbert transformer connected to an output terminal of the quadrature component extractor and configured to Hilbert-transform a signal transmitted from the quadrature component extractor, and an adder connected to an output terminal of the in-phase component extractor and an output terminal of the Hilbert transformer and configured to receive both an output signal of the in-phase component extractor and an output signal of the Hilbert transformer and to add the two received signals to each other, wherein the second-order harmonic detection unit outputs the second-order harmonic component of the input focused signal.