Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Average spirograms (with indications of mean and standard deviation) reconstructed from the pneumotachograph signal (PNT) and the non-contact vibrometer using airborne ultrasound (SONAR) in the whole study population, with the SONAR in front of the subjects (A) or in their back (B). The Y-axis indicates tidal volume (VT) or SONAR-related tidal volume displacement (both in arbitrary units to be comparable).
