US4337779A
Expired / Lapsed
US
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Physiological event detector
Assignee: Medtronic Inc
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Filing: 1980-08-11
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Granted: 1982-07-06
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Expires: 2000-08-11
Abstract
Abstract A physiological event detector including apparatus for receiving and detecting an electrical signal corresponding to a physiological event. The apparatus produces a logic level output when the input signal meets both passband energy criteria and time duration criteria. The structure of the invention includes a filter for selecting the passband criteria and digital timing circuitry for determining how long the passband signal exceeds a minimum energy threshold.
Inventors
- 👤 Richard P. Spevak
- 👤 Lynn D. Hansen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:32
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/05; A61B5/053; A61B5/0538; A61B5/02; A61B5/026; A61B5/0295; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/365; G; G01; G01R; G01R29/00; G01R29/02; G01R29/027
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
117 words
An improved physiologic waveform discriminator for detecting the mechanical pumping action of the heart based upon an impedance plethysmograph signal produced by an impedance plethysmograph coupled to the heart for producing a time varying electrical plethysmograph signal determined by the instantaneous volume of heart, wherein said improvement comprises; frequency selective means for amplifying passband components of said plethysmograph signal for producing a passband signal; time measuring circuitry activated when said passband components of said plethysmograph signal exceed a predetermined level for measuring the time period duration that said passband components of said plethysmograph signal exceed said predetermined level; and, output circuitry for producing an output detection signal when said time period duration exceeds a preset minimum duration.
Claim 2
Dependent Claim
117 words
An improved physiologic waveform discriminator for detecting the mechanical pumping action of the heart based upon an impedance plethysmograph signal produced by an impedance plethysmograph coupled to the heart for producing a time varying electrical plethysmograph signal determined by the instantaneous volume of heart, wherein said improvement comprises; frequency selective means for amplifying passband components of said plethysmograph signal for producing a passband signal; time measuring circuitry activated when said passband components of said plethysmograph signal exceed a predetermined level for measuring the time period duration that said passband components of said plethysmograph signal exceed said predetermined level; and, output circuitry for producing an output detection signal when said time period duration exceeds a preset minimum duration.
Claim 3
Dependent Claim
31 words
The discriminator of claim 1 wherein said frequency selective means includes a passband amplifier of nominal unity gain for attenuating signal components below approximately 0.5 Hertz and above approximately 20 Hertz.
Claim 4
Dependent Claim
123 words
The discriminator of claim 2 wherein said time measuring circuitry includes: A switched oscillator coupled to said frequency selective means for producing a squarewave output if said passband signal is below a minimum threshold, and for producing a continuous logic level output if said passband signal exceeds said minimum threshold; a clock means activated by said logic level signal for supplying clock pulses to counter means; said counter means for accumulating clock pulses for the period of time that said passband signals exceeds said minimum threshold; and, output circuitry means coupled to said counter means for producing an output detection signal when said counter accumulates a preset number of clock counts indicating that said impedance plethysmograph signal has exceeded a predetermined time period.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-05 | 1986-01-04 | 1986-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-05 | 1990-01-04 | 1990-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-05 | 1994-01-04 | 1994-07-06 | $7700.00 | Window Closed / Lapsed |