US3790890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for measuring a time interval
Assignee: US Philips Corp
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Filing: 1972-04-13
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Granted: 1974-02-05
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Expires: 1992-04-13
Abstract
Abstract Device for measuring a time interval which comprises a capacitor which is charged during a first time interval and is discharged during a second time interval and also comprises two resistors which are connected to the inputs of an operational amplifier and to the capacitor in a manner such that the ratio between the charge and the discharge times is proportional to the ratio between the values of the resistors. By making this resistance ratio one to ten thousand short time intervals in the nanosecond range may be converted into time intervals which lie in the microsecond or millisecond range and hence can be measured with a higher degree of accuracy.
Inventors
- 👤 F Doittau
- 👤 J Ythier
- 👤 M Herbert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:12
CPC Classifications
G; G04; G04F; G04F10/00; G04F10/10; G04F10/105
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
211 words
A device for measuring a time interval comprising a capacitor, means for charging the capacitor during a first time interval which depends upon the time interval to be measured, means for discharging the capacitor during a second time interval which is related to the first time interval, and means for measuring the second time interval, said charging means including a first resistor and means for connecting said resistor to a voltage source during the first time interval, and the discharging means includes an operational amplifier having a first input terminal connected to the capacitor and a second input terminal connected via a second resistor to said voltage source, means connecting a third resistor between the amplifier output and said first input terminal and a fourth resistor between the amplifier output and said second input terminal of the operational amplifier in a manner such that the ratio between the first and second time intervals is proportional to the ratio between the resistance values of the fourth and third resistors, and wherein the means for measuring the second time interval includes a voltage comparator having one input connected to said second input terminal and the other input connected to a reference line to which the voltage source and the capacitor also are connected.
Claim 2
Independent Claim
211 words
A device for measuring a time interval comprising a capacitor, means for charging the capacitor during a first time interval which depends upon the time interval to be measured, means for discharging the capacitor during a second time interval which is related to the first time interval, and means for measuring the second time interval, said charging means including a first resistor and means for connecting said resistor to a voltage source during the first time interval, and the discharging means includes an operational amplifier having a first input terminal connected to the capacitor and a second input terminal connected via a second resistor to said voltage source, means connecting a third resistor between the amplifier output and said first input terminal and a fourth resistor between the amplifier output and said second input terminal of the operational amplifier in a manner such that the ratio between the first and second time intervals is proportional to the ratio between the resistance values of the fourth and third resistors, and wherein the means for measuring the second time interval includes a voltage comparator having one input connected to said second input terminal and the other input connected to a reference line to which the voltage source and the capacitor also are connected.
Claim 3
Dependent Claim
35 words
A measuring device as claimed in claim 1, characterized in that the ratio between the resistance values of the fourth and third resistors are chosen to be of the order of one to ten thousand.
Claim 4
Dependent Claim
40 words
A measuring device as claimed in claim 1 wherein said means for connecting the first resistor to said voltage source comprises a switch connected in series with the first resistor so as to pass current during the first time interval.
Claim 5
Dependent Claim
80 words
A measuring device as claimed in claim 1 further comprising a gate diode connected between the first resistor and the capacitor and a compensating diode connected between the second resistor and the amplifier second input terminal, and wherein said connecting means comprises a switch connEcted between the junction point of the first resistor and the gate diode and said reference line so as to pass current outside of the first time interval and to pass no current during this interval.
Claim 6
Dependent Claim
92 words
A measuring device as claimed in claim 1 for measuring the duration of a pulse delivered by a pulse source wherein the pulse source comprises said voltage source to which the first resistor is connected in series with a diode, a compensating diode connected in series with the second resistor, and a storage device coupled between the pulse source and the second resistor which stores and maintains the voltage amplitude of the pulse source, and a control input provided to reset the storage device to zero on termination of the time measurements.
Claim 7
Independent Claim
212 words
A device for measuring time intervals comprising, a source of voltage, a capacitor, a first resistor connected to the capacitor as a part of a charge circuit therefor, means for selectively connecting said voltage source to said capacitor charge circuit to charge the capacitor during a first time interval determined by the time interval to be measured, an operational amplifier having first and second input terminals and an output terminal, means including said operational amplifier for discharging the capacitor during a second time interval that is substantially longer than said first time interval and is in a given ratio to the first time interval, a second resistor, means connecting the first input terminal of the amplifier to the capacitor and the second input terminal to said voltage source via said second resistor, third and fourth resistors, means connecting the third resistor between the amplifier output terminal and the first input terminal and the fourth resistor between said amplifier output terminal and said second input terminal, the resistance values of said third and fourth resistors being chosen in the same ratio as said given ratio between the second and first time intervals, and means for measuring the second time interval having an input terminal connected to the second input terminal of the amplifier.
Claim 8
Independent Claim
212 words
A device for measuring time intervals comprising, a source of voltage, a capacitor, a first resistor connected to the capacitor as a part of a charge circuit therefor, means for selectively connecting said voltage source to said capacitor charge circuit to charge the capacitor during a first time interval determined by the time interval to be measured, an operational amplifier having first and second input terminals and an output terminal, means including said operational amplifier for discharging the capacitor during a second time interval that is substantially longer than said first time interval and is in a given ratio to the first time interval, a second resistor, means connecting the first input terminal of the amplifier to the capacitor and the second input terminal to said voltage source via said second resistor, third and fourth resistors, means connecting the third resistor between the amplifier output terminal and the first input terminal and the fourth resistor between said amplifier output terminal and said second input terminal, the resistance values of said third and fourth resistors being chosen in the same ratio as said given ratio between the second and first time intervals, and means for measuring the second time interval having an input terminal connected to the second input terminal of the amplifier.
Claim 9
Dependent Claim
45 words
A measuring device as claimed in claim 6 wherein said selective connecting means comprises a switching device connected in series with the capacitor charge circuit and arranged to pass current during the first time interval and to block the current during the second time interval.
Claim 10
Dependent Claim
74 words
A measuring device as claimed in claim 6 wherein said selective connecting means comprises a switching device connected in shunt with the capacitor and arranged to pass current during the second time interval and to block the current during the first time interval, a first diode connected in series with the capacitor in the charge circuit thereof, and a second diode connected in series with the second resistor and the amplifier second input terminal.
Claim 11
Dependent Claim
53 words
A measuring device as claimed in claim 8 wherein said switching device comprises, third and fourth diodes each connected in a shunt circuit with the capacitor, and first and second multivibrator circuits coupled to said third and fourth diodes to selectively control the conduction thereof to provide said first and second time intervals.
Claim 12
Dependent Claim
48 words
A measuring device as claimed in claim 6 wherein said measuring means includes a comparator having one input connected to the second input terminal of the amplifier and a second input connected to a voltage reference line to which the voltage source and the capacitor are also connected.
References Cited (Backward Citations)
US2269603A
Cited
US3296581A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |