US3761874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic presetting of vibrator phase-lock circuits
Assignee: Individual
•
Filing: 1972-06-26
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Granted: 1973-09-25
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Expires: 1992-06-26
Abstract
Abstract In seismic geophysical surveying using one or more servocontrolled vibrators as the source of varying-frequency wave energy, phase-locking of the vibrator output to the input pilot wave form is essential to the proper compositing of both sequentially received waves and simultaneous inputs by two or more vibrators. By the present invention, the phase lock-in time during which non-coherent signals may be produced is minimized by automatically sampling the phase and the gain errors shortly following each signal initiation, and using the samples to update the preset values for each subsequent signal generation.
Inventors
- 👤 Production Co Amoco
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:09
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/02; G01V1/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
143 words
In an apparatus for generating seismic waves in seismic geophysical surveying comprising a servo-controlled vibrator, a pilot-wave source for said vibrator, a conductor including variable phase-shift means connecting said source to said vibrator, and feedback means responsive to the outputs of said source and of said vibrator, including error-signal producing means responsive to the instantaneous phase relation between said pilot wave and said vibrator output and actuating said phaseshift means to shift the phase of said pilot waves to maintain said outputs substantially in a phase-locked condition, the improvement comprising means for sampling the output of said error-signal producing means a fixed time interval after the start of each pilot signal, and means responsive to said sampling means for producing for each subsequent pilot signal an optimum proportionate value of initial error signal to minimize the time interval of attaining said phase-locked condition.
Claim 2
Dependent Claim
143 words
In an apparatus for generating seismic waves in seismic geophysical surveying comprising a servo-controlled vibrator, a pilot-wave source for said vibrator, a conductor including variable phase-shift means connecting said source to said vibrator, and feedback means responsive to the outputs of said source and of said vibrator, including error-signal producing means responsive to the instantaneous phase relation between said pilot wave and said vibrator output and actuating said phaseshift means to shift the phase of said pilot waves to maintain said outputs substantially in a phase-locked condition, the improvement comprising means for sampling the output of said error-signal producing means a fixed time interval after the start of each pilot signal, and means responsive to said sampling means for producing for each subsequent pilot signal an optimum proportionate value of initial error signal to minimize the time interval of attaining said phase-locked condition.
Claim 3
Dependent Claim
58 words
Apparatus as in claim 1 wherein said feedback means comprises an automatic-gain-controlled amplifier and including also means for sampling the output of said amplifier at said fixed time interval after the start of each pilot signal, and means responsive to said output-sampling means for establishing an optimum initial gain value of said amplifier for each subsequent pilot-signal generation.
Claim 4
Dependent Claim
50 words
Apparatus as in claim 2 in which said sampling means comprises means responsive to the starting of a pilot signal, and delay means triggered by said pilot-signal-responsive means for producing at the end of a predetermined time interval an output pulse which actuates said sampling means to take said samples.
Claim 5
Dependent Claim
45 words
Apparatus as in claim 3 in which said pilot-signal-responsive means comprises means for rectifying said pilot signal, and said delay means comprises a mono-stable multivibrator, and adjustable voltage-level-comparing means to trigger said multivibrator when the amplitude of said rectified pilot signal reaches a preset level.
Claim 6
Dependent Claim
42 words
Apparatus as in claim 2 including means to compare the output amplitude of said automatic-gain-controlled amplifier with a standard value, and means responsive to said amplitude-comparing Means to increase or decrease a stored gain-presetting voltage by an adjustable factor K or 1/K.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |