Study And Implementation For Algorithm Of Weak Signal Detection Based On FPGA

In today’s society, with the weak signal detection theory matures and graduallyimproving of the performance of digital devices, more and more weak signal detectiontechniques have been applied to the actual work and daily lives. The nature of chaoticalgorithm makes itselsf unique in the weak signal detection. Chaotic system will changestrongly when a small signal input, but it is very calm under the noise input. The paper hasapplied duffing oscillator chaotic algorithm to radio signal detection, and usingvariance-frequency figure to judge existence of weak signal. By statistical variance ofchaotic sequence’s change trend in noise, if a variance of a frequency appears a largefluctuation compared with others, this value is the frequency of the signal detected.Firstly, paper makes comparison between duffing chaotic algorithm and subspacealgorithm, the former is more advance through simulation of real signal and hardwaresource occupied. Then, paper elaborates design process of each module in chaotic detectionsystem, Including digital-analog acquisition module, digital down conversion module andchaos algorithm module which are designed and implemented using verilog hardwarelanguage. In the end, FPGA transmits the results to host machine through the serial port,then the latter draws variance-frequency diagram with matlab to identify whether there isthe presence of weak signal.By using test of actual signal data, the design could detect thesignal which signal to noise ratio reaches at-30dB. Furthermore, hardware resourcesconsumption is reasonable, and the design is easy to implement.