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US3675643A
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Cardiac tachometer
Assignee: Spectramed Inc
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Filing: 1970-09-04
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Granted: 1972-07-11
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Expires: 1990-09-04
Abstract
Abstract This application relates to means for measuring and recording the frequency of repetitive events which may be subject to large changes in frequency, and is particularly useful in connection with the measuring and recording of heartbeats. This is accomplished by generating a train of pulses responsive to events of interest, establishing a dc potential responsive to the frequency of said train of pulses, generating a linear sawtooth pulse whose amplitude is responsive to the frequency of the applied pulses and to said dc potential, comparing said amplitude of said sawtooth pulses with a reference voltage, and modifying said dc potential responsive to the difference between said reference voltage and said sawtooth pulse amplitude, and providing means responsive to the magnitude of said dc potential to indicate the frequency of the pulses of interest.
Inventors
- 👤 Horst Funfstuck
- 👤 Shmuel Elazar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:41
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/024; A61B5/0245
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
A cardiac tachometer comprising: means to establish a train of pulses responsive to heartbeats; means to establish a dc potential responsive to said train of pulses; means to establish a sawtooth pulse responsive to said dc potential and to the frequency of such train of pulses; means to establish a reference voltage; means for comparing the potential of the amplitude of said sawtooth pulse with a reference voltage; means for modifying said dc potential responsive to the difference between the potential of the amplitude of said sawtooth pulses and said reference voltage; and readout means responsive to said dc potential to indicate the frequency of said heartbeats.
Claim 2
Dependent Claim
107 words
A cardiac tachometer comprising: means to establish a train of pulses responsive to heartbeats; means to establish a dc potential responsive to said train of pulses; means to establish a sawtooth pulse responsive to said dc potential and to the frequency of such train of pulses; means to establish a reference voltage; means for comparing the potential of the amplitude of said sawtooth pulse with a reference voltage; means for modifying said dc potential responsive to the difference between the potential of the amplitude of said sawtooth pulses and said reference voltage; and readout means responsive to said dc potential to indicate the frequency of said heartbeats.
Claim 3
Dependent Claim
136 words
A cardiac tachometer according to claim 1, in which said means for establishing a train of pulses responsive to said heartbeats includes a pulse detector responsive to the R pulse of said heartbeat, said R pulse detector comprising an RC circuit responsive to said first mentioned train of pulses, means to apply to said RC circuit a potential responsive to the potential of the train of pulses arising from that fraction of the R portion of the pulse whose amplitude is in excess of the amplitude of the remaining portions of said pulses, means responsive to said potentials at said RC circuit to generate a train of square wave pulses at the frequency of said R wave fraction, and means responsive to the frequency of such train of square waves to generate the aforesaid dc potential.
Claim 4
Dependent Claim
37 words
In the cardiac tachometer of claim 1, said means to establish a dc potential, including an RC circuit, and said means for modifying said dc potential, including means to apply said potential difference to said RC circuit.
Claim 5
Dependent Claim
190 words
In the cardiac tachometer of claim 1 in which said means for establishing a train of pulses includes a pulse detector responsive to the R pulse in which said means for establishing a train of pulses responsive to said heartbeats comprises an RC circuit, said means for comparing said dc potential with said reference potential, comprising means to establish a reference potential corresponding to the frequency of heartbeats of rate less than normal heartbeat rate and a second reference voltage corresponding to a frequency greater than the normal heartbeat rate frequency and at a potential higher than the potential of said first mentioned reference potential and means for comparing the potential of the amplitude of the sawtooth pulse with each of said reference potentials, means for applying the difference between the amplitude potential and the said lower potential to said RC circuit when said lower potential is in excess of the potential of said amplitude potential and means for discharging the RC circuit when the potential of said amplitude is in excess of said higher potential, and establishing a dc potential responsive to the frequency of said train of pulses.
Claim 6
Dependent Claim
164 words
A cardiac tachometer according to claim 1, in which said means for establishing a train of pulses responsive to said heartbeats includes a pulse detector responsive to the R pulse of said heartbeat, said R pulse detector comprising an RC circuit responsive to said first mentioned train of pulses, means to apply to said RC circuit a potential responsive to the potential of the train of pulses arising from that fraction of the R portion of the pulse whose amplitude is in excess of the amplitude of the remaining portions of said pulse, means responsive to said potentials at said RC circuit to generate a train of square wave pulses at the frequency of such train of square waves at the frequency of said R wave fraction and means responsive to the frequency of such train of square waves to generate the aforesaid dc potential, and said means for modifying said dc potential, including means to apply said potential difference to said RC circuit.
Claim 7
Dependent Claim
297 words
A cardiac tachometer according to claim 1, in which said means for establishing a train of pulses responsive to said heartbeats includes a pulse detector responsive to the R pulse of said heartbeat, said R pulse detector comprising an RC circuit responsive to said first mentioned train of pulses, means to apply to said RC circuit a potential responsive to the potential of the train of pulses arising from that fraction of the R portion of the pulse whose amplitude is in excess of the amplitude of the remaining portions of said pulse, means responsive to said potentials at said last named RC circuit to generate a train of square wave pulses at the frequency of said train of pulses to generate the aforesaid dc potential, said means for modifying said dc potential including means to apply said potential difference to said first mentioned RC circuit, and said means for comparing said dc potential with said reference potential, comprising means to establish a reference potential responsive to the frequency of heartbeats of rate less than normal heartbeat rate and means for establishing a second reference voltage responsive to a frequency greater than the normal heartbeat rate frequency and at a potential higher than the potential said first mentioned reference potential and comparing the potential of the amplitude of the sawtooth pulse with each of said reference potentials, means for applying the difference between the amplitude potential and the said lower potential to said first named RC circuit when said lower potential is in excess of the potential of said amplitude potential and means for discharging the RC circuit when the potential of said amplitude is in excess of said higher potential, and means for establishing a dc potential responsive to the frequency of said train of pulses.
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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |