It is often important to synchronize the captured and displayed OCT B-scan images with an external scanner that is operating in a periodic fashion (e.g. linear or raster scan, rotational or helical scan, etc.). The component driving the external scanner (e.g. arbitrary waveform generator card, spinning motor, etc.) must generate a digital pulse once per period which is used by the DAQ board to provide this image synchronization. This synchronization pulse is provided to the DAQ on its Image_sync trigger input (rising edge active).