The Weak Signal Detection Technology Based On Duffing Oscillator And Its Field Programmable Gate Array Implementation

A weak signal detection system based on FPGA is proposed in this paper.The algorithm of detecting weak signal,which under the strong noise,based on Duffing chaotic oscillator theory is researched,the fourth order runge kutta algorithm(RK4)is applied to solve the duffing chaotic differential equation and implemented in field programmable gate array(FPGA).The system finishes the analog-to-digital conversion of the signal to be measured,the calculation of Duffing equation,discriminate the state of Duffing system and the calculation of signal frequency.And finally it displays the recognition result on OLED.In the process of system design,the recursive sequence is applied to calculate sine value for more efficient hardware resource usage;In the part of solution duffing equation with four order runge kutta method,according to the principle of iteration,multi-channel selector is used to achieve the calculation scheduling.The IP cores,such as Multiplier,Counter and Signal-port ROM,are applied for making better use of the FPGA resources;Considering the obvious differences of phase diagram between two conditions of chaos and large cycle,the method based on the phase diagram segmentation is proposed,which is easy to implement and does not affect the test results,compared with the traditional method.The VHDL hardware description language is employed to design the Duffing system and use three ways to verify the design result.Firstly,fixed-point number computation results with FPGA compared with fixed-point number computation results with MATLAB,the correctness of the duffing equation is verified.Then,each sub-module is validated by Vivado,and the integrated system is implemented on the Zedboard hardware platform.The experiments show that the system can detect the signal which have the same frequency with the system signal.