Testing device for inspecting an object

Claim 1

In a supersonic testing system for inspecting an object: means for generating recurrent high-energy exciting pulses, an electromechanical transducer, an electric connection between the generator and the transducer for applying the exciting pulses thereto, the electromechanical transducer conVerting the exciting pulses into mechanical energy, transmitting the mechanical energy into the object, receiving reflected or echo mechanical energy from the object, and transforming the echo mechanical energy into corresponding electric echo signals, an echo signal amplifier having an input, an electric connection between the transducer and the amplifier for transmitting the electric echo signals to the amplifier input, and blocking means for preventing the exciting pulses from passing through the amplifier, said blocking means including a clipping stageconnected in parallel with the transducer and comprising at least one pair of Zener diodes having a turn-on time shorter than the rise time of the exciting pulse, the diodes of said pair being connected in opposed series, a commutation stage comprising at least one field effect transistor, said commutation stage being connected between the clipping stage and the amplifier, and a control circuit applying to the field effect transistor of the commutation stage a blocking pulse during the duration of the exciting pulse and leaving it in a conductive state the rest of the time.