Variable threshold for rate volume monitor
US4788456A · kind A · utility
3Cited by
2References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 27, 1987 |
| Grant date | Nov 29, 1988 |
| Priority date | — |
| Expiry date | Jul 27, 2007 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/087
- WIPO fieldMedical technology
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.