The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 31, 1987
Filed:
Oct. 18, 1982
Cameron B Wason, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A vibrator seismic source has a hydraulic system, including a pad, for applying reciprocating forces to the ground and sensor means for generating a feedback signal representative of the force applied to the ground. Circuitry is provided for generating a pilot signal representative of the desired force to be applied to the ground. The pilot and feedback signals are single sideband shifted to increase both frequencies by a predetermined frequency. The high frequency pilot and feedback signals have their phase difference conventionally detected and provided to a digital computer for phase shifting the signal for controlling the vibrator so that the feedback signal is in phase with the pilot signal. In another embodiment, the instantaneous phase of each signal is computed continuously by a digital computer. The control signal digital representation is corrected to correspond with the pilot digital representation and an analog output signal is generated to provide the proper analog control signal.