The Research Of Sending Or Receiving Focusing Algorithms Of FPGA-based Ultrasonic Phased Array

In the traditional ultrasonic phased array system, the delay amount of delay technique is calculated by the pc, and then through the bus technology such as USB, the results are send to the delay control circuit, and analog switch means are used, such as multiplexer and analog delay line, to complete the delay of each channel, so this system is not only bulky, but very low degree of integration.To solve this problem, this paper researches how to achieve the ultrasonic phased array focusing algorithm which is based on FPGA. This method uses a digital system to calculate the amount of the delay, which greatly improves the speed of operation and reduce the volume and improve the integration. When achieving the ultrasound phased array focusing algorithm which is based on FPGA, in order to further improve the accuracy of the delay, this paper uses floating-point formats of standard IEEE-754to design each modules, including add/subtract modules, multiplication and division modules and cosine trigonometric module. In the division and cosine trigonometric module, the CORDIC algorithm is used. By analyzing the results of different iterations, we know that when the number of iteration is16, the accuracy of5ns is meeting the goal.Compared to fixed-point CORDIC algorithm, with the same number of iterations, the precision of floating-point CORDIC algorithm is relatively high. It will help improve the accuracy of the delay, then help to improve the final results of the focusing effect. The pipeline and parallel designs are used to increase the clock frequency, thereby increasing the speed of computing. Then, some FPGA modules are designed to simulate the characteristics of ultrasonic phased array. Finally, the output data was smoothly processed in DSP, and the effect is good.