Patent ID: 7728986

Claim:
A digital detection method for an analog tomographic signal, the method comprising: receiving an amplitude-modulated analog signal containing tomographic information, the analog signal having a modulation frequency, f λi ; converting the analog signal into a digital signal at a sampling frequency, f s to produce a number of samples, K; multiplying the digital signal by an in-phase reference signal to obtain an in-phase signal component, the in-phase reference signal having the frequency, f λi ; multiplying the digital signal by a quadrature reference signal to obtain a quadrature signal component, the quadrature reference signal having the frequency, f λi ; passing the in-phase signal component through a K-point averaging filter; passing the quadrature signal component through the K-point averaging filter; computing a signal amplitude based on the filtered in-phase signal component and the filtered quadrature signal component, the signal amplitude being representative of the tomographic information; and outputting the demodulated signal amplitude.