| 摘要 |
<p>The present invention relates to a method and apparatus (10) for determining the instantaneous value of one or more properties of a sample examined by means of an interference technique, such as optical coherence tomography. The apparatus (10) includes an interferometer (12) which produces an interferogram signal (14), a phase comparator (16), a voltage-controlled oscillator VCO (18) and a low-pass filter (22). The phase comparator (16), VCO (18) and low-pass filter (22) together form an feedback loop in the form of phase-locked loop (30) wherein an output (24) of the low-pass filter (22) is linearly related to a scatterer's velocity ξs in the sample. The apparatus also includes a phase shifter (32), a mixer (38) and a low-pass filter (42) which generate a reflectivity signal (44).</p> |
