In this thesis, a 16-channel experimental phased array ultrasonic testing system is originally designed and developed, upon which several key technologies are thoroughly studied.
In this paper, according to the far field direction theory and near field acoustic pressure distribution theory of the phased array transduer, the authors analyesd and calculated the acoustic field. On this basis, the change range of aperture and its applicable depth to the transducer(64 units) of the phased array ultrasonic diagnostic B-sanner in aperture focusing were presented.
In the following chapters, a 16-channel experimental phased array ultrasonic testing system is thoroughly explained, including digital beam forming, low noise programmable amplification of received ultrasound signal, multi-channel hi-speed hi-precision data acquisition, hi-speed real-time processing of multi-channel ultrasound signal, and hi-speed data transfer based on PCI bus. In addition, the frame of software system is built.
PWA-1 automatic ultrasonic phased array testing system developed in our country was introduced,and the future improvement of the system was also described.
The application of industrial ultrasonic phased array detection is still in the introductory stage in China. The key technology is researched and resolving scheme is put forward in the paper.
We use HP5500 ultrasonic diagnostic machine to investigated the changes of calibrated myocardial integrated backscatter (IBS%), magnitude of cyclic variation in integrated backscatter (CVIB), calibration of delayed time of CVIB (DTCV%), and the velocity of endocardial motion of the whole systolic period (VSEM) 30 days after the PTCA.