System for controlling seismic vibrator - to permit injection of pseudorandom- or other broad band signals into the ground

摘要

System includes a feedback loop with a summing circuit having an electrical input signal representative of the desired seismic signal applied to one input terminal thereof and an electrical feedback signal applied to a second input terminal. The feedback signal derives from a transducer connected to a coupling plate of the vibrator and has an amplitude varying instantaneously with coupling plate motion. The output of the summing circuit is applied to the vibrator drive circuit via a phase compensator serving to compensate for phase shift within the vibrator. Arrangmenet permits the vibrator to be used for injection of pseudo-random or other wide band seismic signals into the ground.