The Measures Of Output From Bistable Stochastic Resonance Systems

Stochastic resonance (SR) is a counterintuitive phenomenon of nonlinear dynamic systems wherein the noise (stochastic force) plays a constructive role. This phenomenon has then attracted much attention in the past two decades, and it has been observed that SR can occur in a wide variety of systems. With the development of SR, it has far been found to account for many natural phenomena and shown a large number of applications in different areas of technology, among which signal processing via stochastic resonance is a worth subject to be concerned.For a long time, SR was described as a phenomenon wherein the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular level of noise. However, this description has served to limit the application of SR to signal processing. Parameter-tuning stochastic resonance (PSR) is a more realistic way to handle the phenomenon of SR in a broad sense. Based on the theory of PSR, some key problems of using SR in signal processing are studied, these issues include: the application of intrawell SR in multi-frequency analog signal processing, recovery of the waveform distortion caused by the bistable system and other post treatments, measure of system performance with multi-frequency analog digital input and measurement of system performance of binary digital input. The results are used in signal detecting under the background of the real sea noise. It is important for the development of SR theory and its application in nonlinear signal processing.With the work on a recently proposed phenomenon of SR ?the intrawell SR, we found that intrawell SR is a more effective way to process multi-frequency input. Most of the literatures considering analog input are focused on simple harmonic input, because the output waveform from a bistable system is greatly distorted. As for single harmonic input, the output information can be easily retrieved by some typical methods, such as frequency analysis and a bandpass filter. But when treating a multi-frequency analog signal, there is not a simple method. Based on the analysis of waveform distortion caused by bistable systems, a recovery formula is proposed, and some other post treatments are considered as a whole job. Then a measure on intrawell SR with multi-frequency input is obtained.There are many results on SR with binary digital input. As an extension of our previous works, a dynamic bit error rate (DBER) is obtained in this thesis. The DBER is a more accuracy measure to be used in SR with binary input, because the evaluation of system output is considered more detailedly with the concept of system response speed. The measure mentioned above, and the DBER have been used in the work of signal detection under the background of real sea noise.Using stochastic resonance in signal processing is a subject of more then two field of learning, only some of the key points of SR and the limitations in application are considered in this thesis. In order to join SR with signal processing more closely, further work needs to be done on the subject of using stochastic resonance in signal processing.