Dual-edge sampling with k-clock to avoid aliasing in optical coherence tomography

An Optical Coherence Tomography (OCT) data acquisition and processing circuit for use in producing an OCT image based on a swept-source OCT interference signal, the OCT data acquisition and processing circuit comprising:

• a k-clock configured to selectively output a k-clock signal at any of a plurality of k-clock frequencies ranging from a minimum k-clock frequency to a maximum k-clock frequency;
• an anti-aliasing filter configured to filter the swept-source OCT interference signal, to produce a filtered OCT interference signal, the anti-aliasing filter having a cut-off frequency greater than one-half the minimum k-clock frequency but less than the minimum k-clock frequency;
• and
• an analog-to-digital (A/D) converter circuit coupled to an output of the anti-aliasing filter and configured to sample the filtered OCT interference signal at twice the k-clock frequency, to produce a sampled OCT interference signal;
• wherein the A/D converter circuit comprises first and second A/D converters, the first A/D converter being configured to sample the filtered OCT interference signal at the k-clock frequency, using the k-clock signal, and the second A/D converter being configured to separately sample the filtered OCT interference signal at the k-clock frequency, using a phase-shifted replica of the k-clock signal, the A/D converter circuit further comprising a multiplexer to combine the sampled outputs from the first and second A/D converters to obtain the sampled OCT interference signal.