Multilevel modulation ultrasonic encoding single excitation method based on Golay complementary convolutional codes

Abstract

The invention discloses a multilevel modulation ultrasonic encoding single excitation method based on Golay complementary convolutional codes. The method includes the steps that a multi-element code C=A*B is generated for single encoding excitation by means of convolution operation of an orthocomplementation Golay (A,B) code binary sequence; amplitude modulation and phase modulation of the multi-element code C are achieved through an encoding controller, code element symbols are mapped into electric pulse signals with certain phases and amplitudes, and an ultrasonic probe is excited; excitation conversion factor conversion from C to A and from C to B is conducted on echo signals subjected to encoding excitation, two paths of echo signals are formed, the C code excited once indirectly generates the effect achieved by independent dual excitation of the A code and the B code, and the quasi single excitation technology is formed; the two paths of echo signals are subjected to pulse compression, and ideal encoding is achieved through vector synthesis; finally, complementary Golay (A,B) with the code length Lc being 8 is subjected to encoding excitation and decoding, the functions are simulated, and the encoding excitation effect is verified through FPGA hardware. Compared with a traditional method, echo gain and excitation efficiency are indirectly improved, and the method also has great advantages in the aspects of signal-to-noise ratio, flexibility and implementation performance.

Description

technical field [0001] The invention relates to a multi-element modulation ultrasonic coding single excitation method based on Golay complementary convolution code. Background technique [0002] The coding excitation technology of the ultrasonic phased array system is basically similar to the traditional single pulse excitation technology. It excites the ultrasonic probe by sending electric pulses with a certain phase, amplitude, and pulse width to realize electro-acoustic signal conversion and scan the inside of the workpiece under test. The echo signal is collected and image reconstruction is carried out for analysis. The differences are as follows: the microcosmic performance is that the number of pulses transmitted each time, the phase and the processing scheme of the received echo are inconsistent, and the macroscopic results show that: under the same hardware conditions, the coding excitation technology (software means) can get the same as a single pulse. The same hor...

AI Technical Summary

Problems solved by technology

For example, Jinhyoung Park (2010) of the University of California, University of California (2010) used Golay code excitation technology and a 6dB bandwidth amplifier to achieve ripple within 4dB in the 10-110MHz frequency band, reflecting excellent performance; University of Science and Technology of China (2010) used Chirp signal Modulate the Golay complementary code excitation to incr

Images