Patent US3898481A successfully refreshed from Google Patents.
US3898481A
Expired / Lapsed
US
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Signal pulse detector
Assignee: Cincinnati Electronics Corp
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Filing: 1974-03-28
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Granted: 1975-08-05
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Expires: 1994-03-28
Abstract
Abstract The occurrence of a signal pulse having predetermined characteristics in a waveform susceptible to random, noise variations, including base line drift, is detected with an apparatus including first and second channels driven in parallel by a source of the waveform. The first channel includes a differentiator that drives a voltage level comparator for deriving a gating signal while the waveform has at least a predetermined slope characteristic of the signal pulse. A minimum pulse width detector responds to the output of the comparator to indicate that the predetermined slope has subsisted for at least a predetermined interval. The output of the minimum pulse width detector drives a monostable which derives an output wave having a trailing edge in time coincidence with the maximum pulse width. The outputs of the comparator and monostable are combined in an OR gate which derives a gating voltage for a clamping circuit in the second channel, whereby replicas of the signal pulses from the source are coupled through the clamping circuit at a reference voltage, despite the base line drift. The voltage passed through the clamp is compared with a threshold level for the amplitude of the signal pulse. The output of the monostable is combined with signals passed through the clamping circuit to derive an indication that a valid signal pulse is in the waveform.
Inventors
- 👤 Harold P Glaser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:20
CPC Classifications
H; H03; H03F; H03F3/00; H03F3/30; H03F3/3069; H03F3/3071; H03K; H03K5/00; H03K5/003
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
220 words
Apparatus for detecting the occurrence of a pulse having predetermined characteristics in a waveform susceptible to random, noise variations including base line drift, comprising first and second channels Driven in parallel by a source of the waveform, means in said first channel for deriving a gating signal while the waveform has at least a predetermined slope characteristic of the pulse, a clamping circuit in said second channel for normally blocking passage of said waveform and for normally deriving an output signal having a reference level, and for enabling the pulse from the source to be coupled through the clamping circuit in response to derivation of said gating signal, said clamping circuit including means for referencing the pulse coupled through it to the reference level regardless of the level of the base line drift of the waveform accompanying the signal pulse, said clamping circuit including a series capacitor and a shunt switch normally biased to a low impedance state for maintaining the voltage of one electrode of the capacitor substantially at the reference level, said shunt switch being driven to a high impedance state in response to the gating signal for enabling a voltage that is a replica of the pulse to be developed at the one electrode, and means for detecting the amplitude of the voltage of said one electrode.
Claim 2
Dependent Claim
220 words
Apparatus for detecting the occurrence of a pulse having predetermined characteristics in a waveform susceptible to random, noise variations including base line drift, comprising first and second channels Driven in parallel by a source of the waveform, means in said first channel for deriving a gating signal while the waveform has at least a predetermined slope characteristic of the pulse, a clamping circuit in said second channel for normally blocking passage of said waveform and for normally deriving an output signal having a reference level, and for enabling the pulse from the source to be coupled through the clamping circuit in response to derivation of said gating signal, said clamping circuit including means for referencing the pulse coupled through it to the reference level regardless of the level of the base line drift of the waveform accompanying the signal pulse, said clamping circuit including a series capacitor and a shunt switch normally biased to a low impedance state for maintaining the voltage of one electrode of the capacitor substantially at the reference level, said shunt switch being driven to a high impedance state in response to the gating signal for enabling a voltage that is a replica of the pulse to be developed at the one electrode, and means for detecting the amplitude of the voltage of said one electrode.
Claim 3
Dependent Claim
81 words
The apparatus of claim 1 wherein the means in the first channel for deriving the first signal causes the first signal to be derived a predetermined time subsequent to the initiation of a waveform segment having the at least predetermined slope, and means in said second channel for delaying the waveform that is applied to the gating means by an amount substantially equal to the predetermined time between the derivation of the first signal and the initiation of the waveform segment.
Claim 4
Dependent Claim
21 words
The apparatus of claim 1 further including a source of the waveform, said source being a scanning infrared point source detector.
Claim 5
Dependent Claim
82 words
The apparatus of claim 1 wherein the clamp includes a high input impedance buffer for deriving an output that is a replica of the signal pulse developed at the one electrode, said buffer including a pair of series input diodes and a push-pull output having a pair of transistors, each of said diodes being connected to drive the emitter base junction of a different one of the transistors, each diode having a junction matched to the junction of the transistor it drives.
Claim 6
Dependent Claim
43 words
The apparatus of claim 1 wherein the clamp includes a driver having a push-pull, low impedance output connected in d.c. circuit with said capacitor, a pair of transistors comprising the push-pull, low impedance output, and means for suppressing oscillation in the push-pull output.
Claim 7
Dependent Claim
35 words
The apparatus of claim 5 wherein the means for suppressing oscillation includes a resistor in the collector circuit of one of the transistors and a capacitor shunting the base collector junction of said one transistor.
Claim 8
Dependent Claim
201 words
Apparatus for detecting the occurrence of a pulse having predetermined characteristics in a waveform susceptible to random, noise variations comprising first and second channels driven in parallel by a source of the waveform; means in said first channel for deriving a first signal substantially while the waveform has at least a predetermined slope that is characteristic of the pulse and for deriving a second signal indicative of the first signal having an occurrence of at least a predetermined minimum duration, gate means in said second channel having an output, said gate means normally blocking passage of said waveform while deriving a reference level at the output and for deriving at the output a replica of the waveform while said first signal is being derived; means for deriving a third signal in response to the output level of the gate means deviating from the reference level by at least a predetermined amplitude characteristic of the pulse; and means responsive to the simultaneous occurrence of the second and third signals for deriving a fourth signal indicative of the waveform having the predetermined slope and at least the predetermined amplitude for at least the predetermined minimum duration to indicate the occurrence of the pulse.
Claim 9
Dependent Claim
201 words
Apparatus for detecting the occurrence of a pulse having predetermined characteristics in a waveform susceptible to random, noise variations comprising first and second channels driven in parallel by a source of the waveform; means in said first channel for deriving a first signal substantially while the waveform has at least a predetermined slope that is characteristic of the pulse and for deriving a second signal indicative of the first signal having an occurrence of at least a predetermined minimum duration, gate means in said second channel having an output, said gate means normally blocking passage of said waveform while deriving a reference level at the output and for deriving at the output a replica of the waveform while said first signal is being derived; means for deriving a third signal in response to the output level of the gate means deviating from the reference level by at least a predetermined amplitude characteristic of the pulse; and means responsive to the simultaneous occurrence of the second and third signals for deriving a fourth signal indicative of the waveform having the predetermined slope and at least the predetermined amplitude for at least the predetermined minimum duration to indicate the occurrence of the pulse.
Claim 10
Dependent Claim
78 words
The appAratus of claim 7 wherein said gate means comprises a clamping circuit including a series capacitor and a shunt switch normally biased to a low impedance state for maintaining the voltage of an output electrode of the capacitor substantially at the reference level, said shunt switch being driven to a high impedance state in response to the first signal for enabling a voltage that is a replica of the waveform to be developed at the one electrode.
Claim 11
Dependent Claim
44 words
The apparatus of claim 8 further including means for inhibiting the derivation of the fourth signal in response to pulses in the waveform having the predetermined slope and duration in excess of a predetermined maximum duration characteristic of the maximum duration of the pulse.
Claim 12
Dependent Claim
95 words
The apparatus of claim 9 wherein the means for inhibiting includes means for deriving a binary signal having a predetermined length substantially equal to the predetermined maximum duration, means for driving the shunt switch to the high impedance state in response to the binary signal so that the gate means derives a replica of the waveform while the binary signal has the predetermined length, and means combining the binary signal and the third signal for deriving the fourth signal only in response to the third signal having a duration less than the predetermined maximum duration.
Claim 13
Dependent Claim
81 words
The apparatus of claim 7 wherein the means in the first channel for deriving the first signal causes the first signal to be derived a predetermined time subsequent to the initiation of a waveform segment having the at least predetermined slope, and means in said second channel for delaying the waveform that is applied to the gating means by an amount substantially equal to the predetermined time between the derivation of the first signal and the initiation of the waveform segment.
Claim 14
Dependent Claim
44 words
The apparatus of claim 7 further including means for inhibiting the derivation of the fourth signal in response to pulses in the waveform having the predetermined slope and duration in excess of a predetermined maximum duration characteristic of the maximum duration of the pulse.
Claim 15
Dependent Claim
90 words
The apparatus of claim 12 wherein the means for inhibiting includes means for deriving a binary signal having a predetermined length substantially equal to the predetermined maximum duration, means for enabling the gate means in response to the binary signal so that the gate means derives a replica of the waveform while the binary signal has the predetermined length, and means combining the binary signal and the third signal for deriving the fourth signal only in response to the third signal having a duration less than the predetermined maximum duration.
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) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |