The Design Of High Speed Signal Sampling And Processing System For Lidar

Coherent LDA measure aerosol's speed witch equals to the wind's speed by measuring the Doppler shift of scattered light.Because large amount of Coherent LDA data is received, the high-speed data acquisition and processing is very important. This paper presents a high-speed data acquisition and processing system for Coherent LDA based on FPGA and DSP and given the specific hardware and software design. The system is divided into data acquisition and data processing module.The main working process of this system is: Analog signal is sent to ADC through the op amp and converted into digital signal. In the timing control of FPGA, the data is deposited in the internal FIFO of FPGA. DSP chip reads data from the FIFO and then does FFT when the FIFO becomes full.The system mainly has several advantages: Using 200M, 14bit ADC to sample to ensure spatial resolution of 0.75m and a higher conversion precision; Adopting LVDS data transmission mode to ensure high-speed data transmission and noise restraining; The system that adopts Cyclone III series FPGA chip for logic control supports LVDS signal mode, and the internal PLL provides the necessary high-frequency ADC clock; Data processing using floating-point DSP chip TMS320C6713B can reach the highest 300MHz frequency and the highest instruction execution speed 1800MFLOPS,which is especially suitable for FFT.The system is divided into two independent modules including data acquisition and data processing for universal considerations. User can using two modules individually or in combination according to the site environment.