Research On Miniaturization Front-End Systems Of Ultrasonic Phased Array Imaging

Due to large volume,poor portability and high cost,traditional ultrasonic phased array system is difficult to be widely used in practical detection.Miniaturization and economical efficiency are the trend of ultrasonic phased array system.But there is still a gap between the performance of domestic ultrasonic phased array system and that of foreign advanced instruments.The front-end system of ultrasonic phased array imaging is an important part of ultrasonic phased array system,and its performance determines the imaging quality.Therefore,it is of great significance to study the front-end system of ultrasonic phased array imaging with miniaturization and high performance.In this study,a miniaturized front-end system was designed,and a fast delay algorithm with a precision of 2 ns was studied based on the system.The system not only has high integration,but also has high performance.The work is as follows:(1)Hardware scheme.The hardware scheme of the miniaturized front-end system of ultrasonic phased array imaging was proposed.The system was divided into two parts: the analog front-end and the control board.The analog front-end is used to drive the probe and receive ultrasonic echo signals,and the control board is used to control the analog front-end and transmit data.Finally,the transmitting circuit,receiving circuit and control board circuit were designed.(2)Design of the control program.The program of front-end system was designed based on a single FPGA,including the FPGA program of the transmitting circuit,the receiving circuit,the LVDS serial and parallel conversion and the USB 3.0 data transmission.Based on the system,the beamforming program was proposed.In the transmitting process,the 2 ns delay was achieved by the phase difference method,which is economical and flexible.In the receiving process,the 2 ns delay was realized by the parallel 10-fold interpolation CIC filter algorithm,which improves the detection speed of the system.(3)The test of front-end system.The system has 64 transmit channels and 8receive channels,and the number of channels can be extended.The transmitting circuit of the system could output 0～±100 V pulse,and its frequency could reach 20 MHz.The receiving circuit of the system could sample the high frequency echo signal and has the function of time gain compensation.The delay accuracy of the system is 2ns.The size of system is only 200 mm × 140 mm,and it could be connected with embedded computer such as mini tablet PC through high-speed interface to build a set of ultrasonic phased array system,which is miniaturized and high-performance.