Optical coherence tomography is a high-resolution imaging system. It obtains 2- and 3-dimensional images from scattering materials (e.g. biological tissue). As a non-invasive diagnostic instrument, it is mostly used for ophthalmological examination of the retina. In this application, analog signals are sampled with ADCs so that the resulting digital pattern represents the analog signal as a function of the change in wavelength of the light source.