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US3881167A
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Method and apparatus to maintain constant phase between reference and output signals
Assignee: Pelton Co Inc
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Filing: 1973-07-05
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Granted: 1975-04-29
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Expires: 1993-07-05
Abstract
Abstract A control system for an electro-hydraulically driven vibrator for the purpose of maintaining a constant phase relation between the output signal of the vibrator, passing into the earth, and a reference signal being used to drive the vibrator. The system operates on a digital basis and provides two digital sweep signal generators, each of which provides a train of time spaced voltage pulses of selected magnitude, in accordance with a corresponding train of timespaced time-words signals. One of these is a reference sweep signal generator and has a continuous application of time-words. The second is designed so that the sequence of time-words signals can be modified, that is, time-words are advanced or retarded, thereby effectively shifting the phase of the second, or driver signal generator, with respect to the first, or reference signal generator. The driver signal is used to control an electro-hydraulic vibrator. Feedback signals are provided from the output of the vibrator. These are compared with the reference signal and the result used to provide a feedback error signal, which controls the sequence of time-word signals which are sent to the driver generator. Thus, the two trains of output pulses, from the two generators, are relatively shifted in instantaneous phase, in accordance with the feedback error signal, by the shifting of the time-word sequence to the driver generator.
Inventors
- 👤 Charles R Pelton
- 👤 Kim L Mitchell
- 👤 David H Gauger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:25
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/02; G01V1/04
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
212 words
An electrically controlled vibrator system in which a reference analog signal, or sweep, of selected frequency content and selected time duration is used to control a vibrator to create a seismic output signal, comprising: a. a reference digital signal generator means for producing a reference train of time-spaced digital signals of selected magnitude, responsive to a corresponding first train of timespaced time-word signals; b. a driver digital signal generator means for producing a driver train of time-spaced digital signals of selected magnitude responsive to a corresponding second train of timespaced time-word signal; c. digital to analog conversion means to convert said reference digital signals to a reference analog signal, and to convert said driver digital signals to a driver analog signal; d. means to control and drive said vibrator responsive to said driver analog signal; e. means to derive an output feedback signal indicative of said seismic output signal from said vibrator; and f. means responsive to the phase of said output feedback signal with respect to the phase of said reference analog signal to shift said second train of time-word signals with respect to said first train of time-word signals; whereby said driver analog signal will be correspondingly shifted in phase with respect to the phase of said reference analog signal.
Claim 2
Dependent Claim
212 words
An electrically controlled vibrator system in which a reference analog signal, or sweep, of selected frequency content and selected time duration is used to control a vibrator to create a seismic output signal, comprising: a. a reference digital signal generator means for producing a reference train of time-spaced digital signals of selected magnitude, responsive to a corresponding first train of timespaced time-word signals; b. a driver digital signal generator means for producing a driver train of time-spaced digital signals of selected magnitude responsive to a corresponding second train of timespaced time-word signal; c. digital to analog conversion means to convert said reference digital signals to a reference analog signal, and to convert said driver digital signals to a driver analog signal; d. means to control and drive said vibrator responsive to said driver analog signal; e. means to derive an output feedback signal indicative of said seismic output signal from said vibrator; and f. means responsive to the phase of said output feedback signal with respect to the phase of said reference analog signal to shift said second train of time-word signals with respect to said first train of time-word signals; whereby said driver analog signal will be correspondingly shifted in phase with respect to the phase of said reference analog signal.
Claim 3
Dependent Claim
27 words
The system as in claim 1 in which said means to derive said output feedback signal comprises motion detection means on the base plate of said vibrator.
Claim 4
Dependent Claim
15 words
The system as in claim 2 in which said motion detection means comprises accelerometer means.
Claim 5
Dependent Claim
29 words
The system as in claim 1 in which said means to derive said output feedback signal comprises displacement detection means between the piston and reaction mass of said vibrator.
Claim 6
Dependent Claim
28 words
The system as in claim 1 in which said means to derive said output feedback signal comprises a function of said accelerometer means and said displacement detection means.
Claim 7
Dependent Claim
61 words
The system as in claim 1 in which said means to shift said second train of time-word signaLs of said second driver signal generator includes: a. means responsive to said output feedback signal and said reference analog signal to form a phase error signal, and b. means responsive to said phase error signal to shift said second train of time-word signals.
Claim 8
Dependent Claim
19 words
The system as in claim 6 in which said means to form a phase error signal includes multiply means.
Claim 9
Dependent Claim
10 words
The system as in claim 7 including phase correction means.
Claim 10
Dependent Claim
9 words
The system as in claim 8 including integrator means.
Claim 11
Dependent Claim
22 words
The system as in claim 9 in which said integration is made over an interval of an exact multiple of one cycle.
Claim 12
Dependent Claim
40 words
The system as in claim 10 including means to store said integrator output derived in a first integrating period and to apply the stored output during the succeeding integrating period to control said second time-word signal of said driver generator.
Claim 13
Dependent Claim
87 words
The system as in claim 1 in which said means to shift said second train of time-word signals of said driver signal generator comprises: a. means to form a first square wave from said output feedback signal; b. means to form a second square wave from said reference signal; and c. means responsive to the times of occurrence of the zero crossing times of said first and second square waves to alter the timing of said second train of the time-word signals of said driver signal generator.
Claim 14
Dependent Claim
23 words
The system as in claim 1 including means to transmit a signal corresponding to the output of said vibrator to a separate location.
Claim 15
Dependent Claim
45 words
The system as in claim 1 in which said reference and driver digital signal generator means comprises: a. digital signal generator means, and b. multiplex means to control the input and output of said generator means sequentially between two sets of input and output means.
Claim 16
Dependent Claim
33 words
The system as in claim 1 in which said digital signal generator means comprises digital arithmetic means for calculating said train of time-spaced digital signals responsive to said train of time-spaced time-word signals.
Claim 17
Dependent Claim
79 words
The system as in claim 1 in which said means to derive said output feedback signal includes: a. automatic gain control amplifier means; and b. preset means for said automatic gain control amplifier means; c. said preset means effective from the start of a reference analog signal to a selected time after the start of said reference analog signal; d. said preset means responsive to the automatic gain control signal developed during the preceding reference analog signal or sweep.
Claim 18
Dependent Claim
94 words
The system as in claim 1 in which said means responsive to said phase error signal to shift said train of time-word signals comprises: a. first clock means at frequency F; b. second clock means at frequency 2F; c. pulse width modulator means responsive to said phase error signal; d. first counter means responsive to said first clock means for generating said first train of time-word signals; e. second counter means responsive to said first clock means, said second clock means, and said pulse width modulator for generating said second train of time-word signals.
Claim 19
Dependent Claim
75 words
The system as in claim 17 including counter means to indicate the accumulated difference in time-words between said first and second trains of time-words for a selected length of time, means to store the accumulated value of said difference from the previous sweep, and means to algebraically add the accumulated difference in time words of the current sweep to said stored value, to preset said second counter means prior to initiating the next succeeding sweep.
Claim 20
Dependent Claim
74 words
The system as in claim 17 in which said second counter means is connected to said first clock, except for the duration of the pulses from said pulse width modulator, when said second counter is connected to said second clock for the duration of said pulses when said output signal lags said reference sweep, and is disconnected from both clocks for the duration of said pulses when said output signal leadS said reference sweep.
Claim 21
Dependent Claim
202 words
In an electrically controlled vibrator system in which a reference analog signal, or sweep, of selected frequency content and selected time duration is used to control a vibrator to create a seismic output signal the method of operation comprising: a. generating a reference train of time-spaced digital signals of selected magnitude responsive to a corresponding first train of time-spaced time-word signals; b. generating a driver train of time-spaced digital signals of selected magnitude responsive to a corresponding second train of time-spaced time-word signals; c. converting said reference digital signals to a reference analog signal and converting said driver digital signals to a driver analog signal; d. controlling and driving said vibrator responsive to said driver analog signal; e. deriving an output feedback signal indicative of said seismic output signal from said vibrator; and f. responsive to the phase of said output feedback signal with respect to the phase of said reference analog signal, shifting said second train of time-spaced, time-word signals of said driver signal generator with respect to said first train of time-spaced time-word signals of said reference signal generator; whereby said driver analog signal will be correspondingly shifted in phase with respect to the phase of said reference analog signal.
Claim 22
Dependent Claim
202 words
In an electrically controlled vibrator system in which a reference analog signal, or sweep, of selected frequency content and selected time duration is used to control a vibrator to create a seismic output signal the method of operation comprising: a. generating a reference train of time-spaced digital signals of selected magnitude responsive to a corresponding first train of time-spaced time-word signals; b. generating a driver train of time-spaced digital signals of selected magnitude responsive to a corresponding second train of time-spaced time-word signals; c. converting said reference digital signals to a reference analog signal and converting said driver digital signals to a driver analog signal; d. controlling and driving said vibrator responsive to said driver analog signal; e. deriving an output feedback signal indicative of said seismic output signal from said vibrator; and f. responsive to the phase of said output feedback signal with respect to the phase of said reference analog signal, shifting said second train of time-spaced, time-word signals of said driver signal generator with respect to said first train of time-spaced time-word signals of said reference signal generator; whereby said driver analog signal will be correspondingly shifted in phase with respect to the phase of said reference analog signal.
Claim 23
Dependent Claim
50 words
The method as in claim 20 including the additional steps of shifting said second train of time-word signals to a later value when said output signal leads said reference signal and shifting said second train of time-word signals to an earlier value when said output signal lags said reference signal.
References Cited (Backward Citations)
US3289154A
Cited
US3307648A
Cited
US3307649A
Cited
US3319221A
Cited
US3460648A
Cited
US3698508A
Cited
US3733584A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |