text: The instrumentation needed in order to conduct the data acquisition include a multimode optical fiber, single-mode or few-mode fibers, photon-counting avalanche photodiodes (APDs), multi-tau correlator board, and a computer.
  The first step of data acquisition is probing the tissue with multimode optical fibers that deliver a long coherence length laser light to the tissue. The second step of data acquisition is collecting photons emitted from the tissue surface with single-mode or few-mode fibers. The third step of data acquisition is the APDs detect the photons from the single-mode or few-mode fibers. The APDs act like detectors. The APDs will have a transistor-transistor logic output or binary outputs with the use of transistors. These outputs will be fed into the multi-tau correlator board which will calculate the temporal intensity auto-correlation functions of the detected signal. Then, the function outputs onto the computer where the functions are fitted to the diffusion equation in the previous section in order to determine optical properties about the tissue as well as properties of the scatters or red blood cells such as blood flow index and many more.