US3703168A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fetal heart monitor with particular signal conditioning means
Assignee: Individual
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Filing: 1970-03-30
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Granted: 1972-11-21
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Expires: 1990-03-30
Abstract
Abstract A fetal heart monitor capable of detecting fetal heart activity in a non-invasive manner and in the presence of noise and substantially stronger maternal heart signals. The system is also operative to simultaneously monitor labor contractions in a noninvasive substantially noise free manner, and additionally provides means for selectively displaying the rhythm ECG.
Inventors
- 👤 Richard D Frink
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:20
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/316; A61B5/318; A61B5/344; A61B5/43; A61B5/4306; A61B5/4343; A61B5/4356; A61B5/4362
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
147 words
A non-invasive fetal heart monitor comprising: an amplifier having low input impedance and adapted for connection to a plurality of surface electrodes attached to a mother''s skin; filter means coupled to said amplifier and operative to substantially eliminate 60-cycle signal components; high-Q critically damped active filter means responsive to the fetal complex and operative to provide an enhanced fetal R-wave and to substantially reject spurious signals; said active filter means including first switching means operative to alter the bandwidth of said active filter means to provide relatively wideband operation for detection of rhythm ECG; baseline correction circuitry coupled to said active filter means and operative to maintain the output signal of said active filter means at a stable reference level; and second switching means for bypassing said baseline correction circuitry when said first switching means is operative; said output signal being adapted for application to utilization means.
Claim 2
Dependent Claim
147 words
A non-invasive fetal heart monitor comprising: an amplifier having low input impedance and adapted for connection to a plurality of surface electrodes attached to a mother''s skin; filter means coupled to said amplifier and operative to substantially eliminate 60-cycle signal components; high-Q critically damped active filter means responsive to the fetal complex and operative to provide an enhanced fetal R-wave and to substantially reject spurious signals; said active filter means including first switching means operative to alter the bandwidth of said active filter means to provide relatively wideband operation for detection of rhythm ECG; baseline correction circuitry coupled to said active filter means and operative to maintain the output signal of said active filter means at a stable reference level; and second switching means for bypassing said baseline correction circuitry when said first switching means is operative; said output signal being adapted for application to utilization means.
Claim 3
Dependent Claim
147 words
A non-invasive fetal heart monitor comprising: an amplifier having low input impedance and adapted for connection to a plurality of surface electrodes attached to a mother''s skin; filter means coupled to said amplifier and operative to substantially eliminate 60-cycle signal components; high-Q critically damped active filter means responsive to the fetal complex and operative to provide an enhanced fetal R-wave and to substantially reject spurious signals; said active filter means including first switching means operative to alter the bandwidth of said active filter means to provide relatively wideband operation for detection of rhythm ECG; baseline correction circuitry coupled to said active filter means and operative to maintain the output signal of said active filter means at a stable reference level; and second switching means for bypassing said baseline correction circuitry when said first switching means is operative; said output signal being adapted for application to utilization means.
Claim 4
Dependent Claim
147 words
A non-invasive fetal heart monitor comprising: an amplifier having low input impedance and adapted for connection to a plurality of surface electrodes attached to a mother''s skin; filter means coupled to said amplifier and operative to substantially eliminate 60-cycle signal components; high-Q critically damped active filter means responsive to the fetal complex and operative to provide an enhanced fetal R-wave and to substantially reject spurious signals; said active filter means including first switching means operative to alter the bandwidth of said active filter means to provide relatively wideband operation for detection of rhythm ECG; baseline correction circuitry coupled to said active filter means and operative to maintain the output signal of said active filter means at a stable reference level; and second switching means for bypassing said baseline correction circuitry when said first switching means is operative; said output signal being adapted for application to utilization means.
Claim 5
Dependent Claim
47 words
A non-invasive fetal heart monitor according to claim 1 including active bandpass filter means coupled to said amplifier and having a passband of approximately 0.1 to 1.0 Hz for providing a signal representative of labor contractions simultaneously with the output signal of said high-Q active filter means.
Claim 6
Dependent Claim
194 words
A non-invasive fetal heart monitor comprising: an amplifier having low input impedance and adapted for connection to a plurality of surface electrodes attached to a mother''s skin; filter means coupled to the output of said amplifier and operative to substantially eliminate power line noise frequencies; multistage variable bandwidth active filter means each stage being a high-Q critically damped active filter operative to provide maximum response to the fetal complex and to discriminate against other waveforms; said active filter means being operative in a narrowband mode to provide a first output signal representing an enhanced fetal R-wave and to substantially reject spurious signals, and operative in a relatively wideband mode to provide a second output signal representing a rhythm ECG; first switching means coupled to said active filter means and operative to select said narrow band or wideband mode; baseline correction circuitry coupLed to the output of said active filter means and operative to maintain the output signals of said active filter means at a stable reference level; and second switching means cooperative with said first switching means for bypassing said baseline correction circuitry when said wideband mode is selected by said first switching means.
Claim 7
Dependent Claim
194 words
A non-invasive fetal heart monitor comprising: an amplifier having low input impedance and adapted for connection to a plurality of surface electrodes attached to a mother''s skin; filter means coupled to the output of said amplifier and operative to substantially eliminate power line noise frequencies; multistage variable bandwidth active filter means each stage being a high-Q critically damped active filter operative to provide maximum response to the fetal complex and to discriminate against other waveforms; said active filter means being operative in a narrowband mode to provide a first output signal representing an enhanced fetal R-wave and to substantially reject spurious signals, and operative in a relatively wideband mode to provide a second output signal representing a rhythm ECG; first switching means coupled to said active filter means and operative to select said narrow band or wideband mode; baseline correction circuitry coupLed to the output of said active filter means and operative to maintain the output signals of said active filter means at a stable reference level; and second switching means cooperative with said first switching means for bypassing said baseline correction circuitry when said wideband mode is selected by said first switching means.
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) | 1975-11-21 | 1976-05-22 | 1976-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-21 | 1980-05-22 | 1980-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-21 | 1984-05-22 | 1984-11-21 | $7700.00 | Window Closed / Lapsed |