关键词: 高频超声, 编码脉冲压缩, 线性调频脉冲, 现场可编程门阵列, 信噪比

Abstract:

The high frequency ultrasound imaging has the advantage of high resolution, but it attenuates too fast to detect more information.The coding pulse compression can solve the contradiction between the resolution and the detection depth of high frequency ultrasound. A real-time compression and transmission system of chirp is designed by using field programmable gate array (FPGA),it will enlarge the signal energy to improve detection depth by transmitting a large time-bandwidth products(TBP) chirp,and narrow pulse guarantee resolution is obtained by pulse compression at the receiving end. The experimental results show that the resolution of the high frequency ultrasonic echo signals with center frequency of 10 MHz and 50 MHz are 0.3 mm and 41 μm after pulse compression, respectively. The sidelobe level is 48 dB and 37 dB respectively, and the SNR is increased by 15 dB and 10 dB, respectively.

Key words: high frequency ultrasonic, coding pulse compression, chirp, FPGA, signal to noise ratio