Weak Signal Detection Method Based On Duffing Oscillator And Its Realization

The weak signal can be detected by chaotic oscillator owing to its property of sensitive dependence on initial conditions and of immunity from nosie. A new method to identify chaos is put forward based on the study on the property of the Duffing oscillator,which is to detect weak signal hidden in the background of strong noise in use of Duffing_FFT method.Firstly, the thesis introduce the definition of a chaotic system, Chaos Theory and its development status,as well as the principles and characteristics. The second,describes the detection principle of the chaos and the method of identifying chaos nature, the use of Duffing oscillator to a weak signal detection theory and process.By analyzing the spectrum of the output X of Duffing system,the relations between the altitude of input driver power and the altitude of fundamental wave component of output X is described,and a new method weak signal altitude detection is proposed.Called as Duffing_FFT. This method is the use of the improved FFT algorithm to calculate Duffing oscillator output signal amplitude.According to the relationship between the X-signal amplitude of the the status of the cycle and chaotic Duffing equation input drive power to estimate the weak signal amplitude.The study results show that, compared to traditional methods of detection,the use of this method, not only can improve the accuracy of detection; but also on ease of implementation in the DSP device.The last part of the thesis, the above-mentioned methods have been implementated by DSP, discussed the process of testing this method in detail and applied this method in grounding grid fault detection of weak signal measurement, and given engineering method to implementation of this method in the DSP system.