Digital ADCP Signal Processing System Based On DSP And FPGA

Acoustic Doppler Current Profiler(ADCP)is a device that uses the Doppler effect of ultrasonic signals and the method of ultrasonic ranging to measure the current at different layers of a water flow,which is widely used in marine ocean current observation and river flow measurement.At present,foreign digital ADCP technology is relatively mature,but there is no product launch in China.So it is necessary to study and develop our own ADCP products.Due to the limitations of processor performance and power consumption,the traditional ADCP algorithms and system implementations are mainly realized through the operation of analog circuits.With the improvement of computing performance of DSP and the improvement of resolution and sampling rate of ADC,people are more willing to process the signal in digital circuits.,which can simplify the complexity of the analog circuit and improve versatility,flexibility and stability of the system.After investigating and analyzing,the author fully understood the basic principles of ADCP technology and determined the research and development scheme of ADCP signal processing system.This paper used FPGA technology with parallel high-speed processing capabilities and powerful DSP signal processing technology.It use short-term power spectrum estimation algorithms-complex autocorrelation algorithm and AR power spectrum estimation algorithm to estimate spectrum.The use of superheterodyne technology,TGA amplifier technology,ultrasonic power drive technology achieved high-frequency small signal extraction,amplification and transmission.This paper designed the corresponding principle circuit and PCB circuit board in hardware.Meanwhile it designed the calculation process and corre sponding software program.The functional test in the laboratory environment and the flow rate test in the simple water environment were performed on the finished system.The results showed that the system realized the basic design functions.The ADCP system designed in this paper has features such as strong function,small size,high performance-price ratio,simple structure and strong versatility.Using FPGAs and DSPs,the system's signal acquisition and data processing capabilities are enhanced.It provides an efficient verification platform for the study of ADCP transmit waveform and Doppler frequency shift estimation method.