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:
Jan. 28, 1986
Filed:
Sep. 23, 1983
Applicant:
Inventor:
Ralph A Landrum, Jr, Houston, TX (US);
Assignee:
Western Geophysical Company of America, Houston, TX (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01V / ;
U.S. Cl.
CPC ...
367190 ; 181401 ; 181107 ;
Abstract
A seismic vibrator for shaking the ground is driven by an input sweep signal. A control signal, which is a function of the output force level of the vibrator, modulates the sweep signal to limit the output force level to a value that will prevent ground decoupling. At the beginning of a sweep, an adaptive preset signal over-rides the control signal during a desired initial time portion of the sweep signal. The preset signal for a given sweep is derived from a sample of the control signal that existed during a specified portion of an immediately previous sweep.