US3704416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Sequential sampling system
Assignee: International Business Machines Corp
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Filing: 1970-07-13
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Granted: 1972-11-28
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Expires: 1990-07-13
Abstract
Abstract Although conventional sampling techniques give minimum risetime in the oscillography of repetitive electrical waveforms, system timing uncertainties introduce drift and jitter errors which are typically comparable in magnitude to the cathode ray oscilloscope risetime. By using two sampling oscilloscopes in cascade and in conjunction with special triggering methods, it is possible to reduce the drift by a factor of 10 3 down to a level of less than 10 14 sec./minute. The use of two sampling oscilloscopes in cascade thereby allows highly effective jitter filtering with the result that the new system has greatly improved accuracy in portraying the waveforms of very fast electrical phenomena.
Inventors
- 👤 Brian J Elliott
- 👤 John L Staples
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 22:32
CPC Classifications
G; G01; G01R; G01R13/00; G01R13/20; G01R13/22; G01R13/34; G01R13/342
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
225 words
A sequential sampling system for eliminating the effects of the inherent drift of single sampling systems, comprising: a cascaded pair of sampling oscilloscopes wherein the repetitive analog output signal of the first sampling oscilloscope, produced by sampling a repetitive input signal thereto, is coupled to a second sampling oscilloscope, a triggering means having the output thereof coupled to said second sampling oscilloscope for controlling the sampling time of said second sampling oscilloscope in accordance with the trigger pulses therefrom responsive to be initiated by the said repetitive output signal of said first sampling oscilloscope so as to thereby avoid the effects due to drift in said first oscilloscope, a low-pass filter means coupling the said repetitive output signal of said first sampling oscilloscope to said triggering means so as to thereby diminish the time-jitter that would normally be transmitted through said trigger circuit to said second sampling oscilloscope, and cause said triggering means to sense in time, a point of fixed height on a region substantiallY at the maximum slope of the respective repetitive waveforms of said repetitive output signal of the first sampling oscilloscope to thereby produce said trigger pulses so that the second sampling oscilloscope is thereby synchronized to follow the drift introduced by the first sampling oscilloscope whereby the output signal of said second sampling oscilloscope is displayed as a stationary waveform.
Claim 2
Dependent Claim
225 words
A sequential sampling system for eliminating the effects of the inherent drift of single sampling systems, comprising: a cascaded pair of sampling oscilloscopes wherein the repetitive analog output signal of the first sampling oscilloscope, produced by sampling a repetitive input signal thereto, is coupled to a second sampling oscilloscope, a triggering means having the output thereof coupled to said second sampling oscilloscope for controlling the sampling time of said second sampling oscilloscope in accordance with the trigger pulses therefrom responsive to be initiated by the said repetitive output signal of said first sampling oscilloscope so as to thereby avoid the effects due to drift in said first oscilloscope, a low-pass filter means coupling the said repetitive output signal of said first sampling oscilloscope to said triggering means so as to thereby diminish the time-jitter that would normally be transmitted through said trigger circuit to said second sampling oscilloscope, and cause said triggering means to sense in time, a point of fixed height on a region substantiallY at the maximum slope of the respective repetitive waveforms of said repetitive output signal of the first sampling oscilloscope to thereby produce said trigger pulses so that the second sampling oscilloscope is thereby synchronized to follow the drift introduced by the first sampling oscilloscope whereby the output signal of said second sampling oscilloscope is displayed as a stationary waveform.
Claim 3
Dependent Claim
62 words
The system of claim 1 wherein means including recording means are connected to said second sampling oscilloscope for recording the drift-free, slowed-down replica of said repetitive input signal, said means further including a low-pass filter interconnected between the output signal of said second sampling oscilloscope and said recording means so that the time-jitter of said output waveform is effectively removed without distortion.
Claim 4
Dependent Claim
177 words
A sequential sampling system for reducing the drift normally occurring in a single sampling oscilloscope, comprising: signal producing means for producing a repetitive signal; a first sampling oscilloscope means coupled to said signal producing means for sampling said repetitive signal therefrom and providing a reproduced repetitive signal at the output thereof; trigger-circuit means coupled to the said output of said first sampling oscilloscope means and responsive to be triggered by said reproduced repetitive signal therefrom to produce an output pulse each time said reproduced signal reaches a predetermined voltage level; second sampling oscilloscope means coupled to the said output of said first sampling oscilloscope means and to said trigger-circuit means to sample said reproduced repetitive signal from the said output of said first sampling oscilloscope means each time a pulse is produced by said trigger-circuit means so as to thereby cause said second sampling oscilloscope means to be synchronized to follow the drift introduced into said reproduced repetitive signal by said first sampling oscilloscope means, whereby the output signal of said second sampling oscilloscope means is stationary.
Claim 5
Dependent Claim
177 words
A sequential sampling system for reducing the drift normally occurring in a single sampling oscilloscope, comprising: signal producing means for producing a repetitive signal; a first sampling oscilloscope means coupled to said signal producing means for sampling said repetitive signal therefrom and providing a reproduced repetitive signal at the output thereof; trigger-circuit means coupled to the said output of said first sampling oscilloscope means and responsive to be triggered by said reproduced repetitive signal therefrom to produce an output pulse each time said reproduced signal reaches a predetermined voltage level; second sampling oscilloscope means coupled to the said output of said first sampling oscilloscope means and to said trigger-circuit means to sample said reproduced repetitive signal from the said output of said first sampling oscilloscope means each time a pulse is produced by said trigger-circuit means so as to thereby cause said second sampling oscilloscope means to be synchronized to follow the drift introduced into said reproduced repetitive signal by said first sampling oscilloscope means, whereby the output signal of said second sampling oscilloscope means is stationary.
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) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |