Patent US3802419A successfully refreshed from Google Patents.
US3802419A
Expired / Lapsed
US
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Respiration monitor
Assignee: United States Department of the Air Force
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Filing: 1972-04-11
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Granted: 1974-04-09
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Expires: 1992-04-11
Abstract
Abstract Respiration is monitored by measuring a subject''s impedance by impressing an oscillator-controlled constant current source upon the subject. The output is fed to a differential amplifier, bandpass filtered, and full wave rectified. The differential amplifier can be switched to be fed by separate electrodes on the subject and not connected to the constant current source.
Inventors
- 👤 J Yates
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:01
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/08; A61B5/085; A61B5/086
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
257 words
A system for monitoring the respiration of a subject having a basic body impedance and a changing thoracic impedance comprising: a. an internal oscillator circuit; b. a constant current source controlled by the oscillator; c. a first pair of electrodes fed by the constant current source and adapted to be placed in contact with the subject; d. a differential amplifier connected to the electrodes for measuring the potential difference therebetween; e. a band-pass filter fed by the differential amplifier; f. a full wave rectifier fed by the band-pass filter, the rectified output being a signal proportional to the basic body impedance and a signal proportional to the thoracic impedance change, the rectifier including: 1. first amplifier fed by the band-pass filter, 2. first and second resistors connected to the input terminal of the first amplifier, 3. a first diode having an anode connected to the first resistor and the cathode connected to the output of the first amplifier, 4. a second diode having an anode connected to the output of the first amplifier and the cathode connected to the second resistor, 5. a second amplifier having first and second inputs, the first input being connected to the cathode of the second diode, and 6. a third resistor interposed between the anode of the first diode and the second input of the second amplifier; g. means for measuring the signal proporTional to the basic body impedance level fed by the rectifier; and h. means for measuring the signal proportional to the thoracic impedance change fed by the rectifier.
Claim 2
Independent Claim
257 words
A system for monitoring the respiration of a subject having a basic body impedance and a changing thoracic impedance comprising: a. an internal oscillator circuit; b. a constant current source controlled by the oscillator; c. a first pair of electrodes fed by the constant current source and adapted to be placed in contact with the subject; d. a differential amplifier connected to the electrodes for measuring the potential difference therebetween; e. a band-pass filter fed by the differential amplifier; f. a full wave rectifier fed by the band-pass filter, the rectified output being a signal proportional to the basic body impedance and a signal proportional to the thoracic impedance change, the rectifier including: 1. first amplifier fed by the band-pass filter, 2. first and second resistors connected to the input terminal of the first amplifier, 3. a first diode having an anode connected to the first resistor and the cathode connected to the output of the first amplifier, 4. a second diode having an anode connected to the output of the first amplifier and the cathode connected to the second resistor, 5. a second amplifier having first and second inputs, the first input being connected to the cathode of the second diode, and 6. a third resistor interposed between the anode of the first diode and the second input of the second amplifier; g. means for measuring the signal proporTional to the basic body impedance level fed by the rectifier; and h. means for measuring the signal proportional to the thoracic impedance change fed by the rectifier.
Claim 3
Dependent Claim
13 words
first and second resistors connected to the input terminal of the first amplifier,
Claim 4
Dependent Claim
13 words
first and second resistors connected to the input terminal of the first amplifier,
Claim 5
Dependent Claim
44 words
A respiration monitoring system according to claim 1 which further comprises: a. a second pair of electrodes connected to the subject; and b. means for switching the input to the differential amplifier from the first pair of electrodes to the second pair of electrodes.
Claim 6
Dependent Claim
32 words
A respiration monitoring system according to claim 2 which further comprises a grounded pair of series connected Zener diodes in opposite polarity and connected to the output of the constant current source.
Claim 7
Dependent Claim
22 words
a first diode having an anode connected to the first resistor and the cathode connected to the output of the first amplifier,
Claim 8
Dependent Claim
22 words
a first diode having an anode connected to the first resistor and the cathode connected to the output of the first amplifier,
Claim 9
Dependent Claim
22 words
a second diode having an anode connected to the output of the first amplifier and the cathode connected to the second resistor,
Claim 10
Dependent Claim
22 words
a second diode having an anode connected to the output of the first amplifier and the cathode connected to the second resistor,
Claim 11
Dependent Claim
43 words
A respiration monitoring system according to claim 2 which further comprises: a. a high gain amplifier interposed between the rectifier and the basic body impedance measuring means; and b. a low gain amplifier interposed between the rectifier and the thoracic impedance measuring means.
Claim 12
Dependent Claim
21 words
a second amplifier having first and second inputs, the first input being connected to the cathode of the second diode, and
Claim 13
Dependent Claim
21 words
a second amplifier having first and second inputs, the first input being connected to the cathode of the second diode, and
Claim 14
Dependent Claim
41 words
A respiration monitoring system according to claim 3 which further comprises: a. a terminal for external oscillator connection; and b. means for switching the input of the constant current source from the internal oscillator to the terminal for external oscillator connection.
Claim 15
Dependent Claim
45 words
A respiration monitoring system according to claim 4 which further comprises interposed between the rectifier and the high and low gain amplifiers: a. a grounded holding capacitor; and b. a holding diode having a cathode connected to the holding capacitor for retarding holding capacitor leakage.
Claim 16
Dependent Claim
53 words
a third resistor interposed between the anode of the first diode and the second input of the second amplifier; g. means for measuring the signal proporTional to the basic body impedance level fed by the rectifier; and h. means for measuring the signal proportional to the thoracic impedance change fed by the rectifier.
Claim 17
Dependent Claim
53 words
a third resistor interposed between the anode of the first diode and the second input of the second amplifier; g. means for measuring the signal proporTional to the basic body impedance level fed by the rectifier; and h. means for measuring the signal proportional to the thoracic impedance change fed by the rectifier.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-08 | 1977-10-08 | 1978-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-08 | 1981-10-08 | 1982-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-08 | 1985-10-08 | 1986-04-09 | $7700.00 | Window Closed / Lapsed |