Figure 3From: Evaluation of an ambulatory system for the quantification of cough frequency in patients with chronic obstructive pulmonary diseaseRepresentative recording of talking and laughing. VT = tidal volume; Fb = breathing frequency; Mic = contact microphone output; SE = sound envelope; HR = heart rate; ECG = electrocardiograph tracing; Posture = upright. The shaded bar contains a burst of laughing. Entire duration of depicted recording is 1-min and 37-sec.Back to article page