The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 15, 1980
Filed:
Mar. 15, 1978
Karl Prestele, Erlangen, DE;
Siemens Aktiengesellschaft, Berlin & Munich, DE;
Abstract
In the illustrated embodiment, applied high frequency flow is divided into a first flow component traversing a known flow impedance and a second flow component directed toward the mouthpiece of a breathing tube. During calibration, the mouthpiece is sealed, and phase adjustments are made such that during measurement, applied flow and first flow component representing signals are essentially in phase and can be combined in an a.c. subtracter to provide a measure of the second flow component. A divider provides the quotient of rectified average pressure and second flow component signals as a measure of the magnitude (Z) of respiratory passageway impedance. A phase difference measurement circuit measures the phase difference between pressure and second flow components and can be switched over during calibration for use in the phase adjustment procedure. The real and imaginary components of respiratory passage impedance can be obtained using sample and hold circuitry responsive to the phase of the second flow component.