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.

Date of Patent:
Nov. 29, 1988

Filed:

Jul. 27, 1987
Applicant:
Inventors:

Robert Urman, Schaumberg, IL (US);

Alfred G Brisson, Kildeer, IL (US);

Christopher Nowacki, Arlington Heights, IL (US);

Assignee:

Trutek Research, Inc., Lake Zurich, IL (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03K / ; H03K / ; H03K / ;
U.S. Cl.
CPC ...
307350 ; 307290 ; 307354 ; 307359 ; 307573 ;
Abstract

A variable threshold circuit is provided for use with a rate volume monitor. A series analog switch is controlled by a comparator which is biased by a voltage divider. During low rate exhalation by a patient the bias keeps the analog switch biased against conduction, and noise is suppressed. When exhalation is at a high rate a resistor is switched by a second analog switch into parallel with one of the resistors of the voltage divider to change the bias to the comparator, and thus to render the first analog switch conductive. At this time the high level of the exhilation signal masks any noise.


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