ZONIC

TRANSIENT ELECTRICAL SIGNAL RECORDER AND REPRODUCER; SCIENTIFIC AND ELECTRICAL APPARATUS AND INSTRUMENTS, PARTICULARLY STATIC AND DYNAMIC FORCE AND TORQUE EXCITATION SOURCES FOR EXCITING STRUCTURES; SERVO-CONTROLLERS FOR REGULATING TORQUE, FORCE, VELOCITY, ACCELERATION, AND DISPLACEMENT OF EXCITED STRUCTURES; HYDRAULIC POWER SUPPLIES FOR HYDRAULICALLY-OPERATED STRUCTURE EXCITERS; FORCE, DISPLACEMENT, AND TORQUE TRANSDUCERS FOR TRANSDUCING INTO ELECTRICAL SIGNALS FORCE, DISPLACEMENT AND TORQUE OCCURRING DURING THE EXCITATION OF A STRUCTURE; ELECTRICAL INTEGRATORS, AMPLIFIERS AND PHASE SHIFTERS FOR MODIFYING ELECTRICAL SIGNALS IN ELECTROHYDRAULIC STRUCTURE-EXCITING SYSTEMS; AND HYDRAULIC ACCUMULATORS, HYDRAULIC FILTERS AND HYDRAULIC ACCUMULATORS FOR USE IN ELECTRO-HYDRAULIC STRUCTURE EXCITING SYSTEMS AND HYDRAULIC VALVES FOR USE IN ELECTRO-HYDRAULIC STRUCTURE EXCITING SYSTEMS