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:
Oct. 16, 1984
Filed:
Apr. 08, 1982
Henry L Burns, St. Helena, CA (US);
Erik W Peterson, Calistoga, CA (US);
Bear Medical Systems, Inc., Riverside, CA (US);
Abstract
A gas flow measuring system employs an oscillating chopper valve alternately to deliver a flow head-generated pressure and a reference pressure to a pressure transducer. The chopper valve is driven by a stepping motor under the control of a microcomputer. The stepping motor drives the valve, with an oscillatory frequency determined by the microcomputer, between a first detented position, in which the flow head-generated pressure is delivered to the transducer, and a second detented position, in which the reference pressure is delivered to the transducer. The electrical signal produced by the transducer is fed to a sample-and-hold circuit, also under the control of the microcomputer, whereby the microcomputer controls the sampling rate of the sample-and-hold circuit. The microcomputer can thus establish an optimal sampling rate in accordance with the oscillatory frequency of the valve. In this manner, very fast sampling rates can be established, thereby minimizing the effects of zero drift in the transducer.