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This paper provides design and development details of the generation of bipolar High Voltage (HV) square wave pulses for the excitation of low frequency ultrasonic transducers. Such a circuit is required for the purpose of ultrasonic inspection of components, particularly where high energy is required to insonify the attenuative medium, such as concrete. A HV (±350 V) square wave pulse has been generated by an ultrafast complementary Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) pair, which is driven by high speed MOSFET drivers. The generated bipolar square wave pulse has been utilized to energize a 108 kHz ultrasonic transducer to operate in the pulse-echo mode for the evaluation of a concrete test block. The receiver amplifier filters the received low-amplitude echo signals, which are reflected back from a discontinuity, and amplifies further for signal to noise ratio enhancement. The pulser board designed has been tested and evaluated for its functionality to measure ultrasonic velocity in the highly attenuative concrete medium up to a depth of 1 m. The measured value of acoustic velocity was compared with the value obtained from the commercially available ultrasonic pulse velocity instrument, and the values obtained are within ±5%.

The novel matrix-based real-time ultrasonic imaging using an ultrasonic camera for immersion application has been proposed in this paper. The proposed ultrasonic camera provides real-time images of mechanical components and the image size is equal to the field of view of the developed matrix-based transducer assembly. For the matrix-based ultrasonic imaging, the addressing-based analog multiplexing scheme has been proposed in such a way that all channels of the specific row are selected simultaneously such as the transducer excitation, data acquisition, data processing and transferring operations are performed concurrently. Similarly, the same operations are performed for remaining all rows sequentially. The developed ultrasonic camera further supports dynamic on-line reconfiguration of the analog front-end hardware, real-time hardware/software-based data processing and data transfer operation. For the experimentation, the entire matrix-based (5 × 5) ultrasonic imaging system for immersion applications has been designed, developed and evaluated in the laboratory. Here we present the performance evaluation of the developed matrix-based ultrasonic camera system by acquiring the real-time images of the water-immersed mechanical objects.