“…While some place it as low as 0.1 Hz in order to maintain a
“pure” signal [21], [49],
[51], [65], [66], [83], [86], [90],
others place it as high as 30 Hz or more in order to eliminate motion artifacts and
other low frequency noise [39], [42],
[44], [60]–[62], [69]. Since similar bandlimits have yet to be identified for
swallowing sounds, studies which use a microphone simply limit the recorded signal
to either the human audible range [21], [32],
[33], [37], [40], [46], [48], [67],
[76]–[78], [86],
[89], [95], [97]–[100], [102], [103], [110],
[112]–[116] or the range of common stethoscopes used in bedside
assessments [13],
[22], [28], [39], [56], [69], [73],
[88], [91], [92]. Typically, this bare minimum amount of
signal processing has traditionally been done for one of two reasons.…”