Sample swallow signals on the left and aspiration signals on the right. Note that swallows are typically longer in duration and dominated by low frequency components. Aspirations come in many flavours, some with noticeable high frequency elements (top and middle graphs on right side), but others with predominantly low frequency components (bottom right graph).
Lee et al. Journal of NeuroEngineering and Rehabilitation 2006 3:14 doi:10.1186/1743-0003-3-14