针对经典随机共振检测大参数信号的困难,提出了基于频域信息交换的随机共振方法,并根据相移的单边带信号调制理论阐述了频域信息交换的随机共振机理.为了克服变尺度随机共振采样频比的制约,给出了基于变尺度频域信息交换的随机共振信号检测方法.数值模拟和信号检测性能分析表明,基于变尺度频域信息交换的随机共振方法具有更有效的采样频比,更便于工程实际的应用.
In the past few decades,stochastic resonance(SR) has attracted considerable attention of researchers due to a curious phenomenon appearing in a nonlinear system:an input weak periodic signal can be amplified and optimized by the assistance of noise.It has been proved that the classical stochastic resonance(CSR) has the adiabatic limit,so the performance of CSR in high-frequency signal detection is restricted in practical engineering.To break the restriction,a number of methods have been suggested,such as re-scaling frequency stochastic resonance(RFSR),parameters normalized stochastic resonance,modulated stochastic resonance,etc.Although the high-frequency signal can be detected by the above methods in specific conditions,there are some problems that restrict their applications in different circumstances.In this paper,a new method,stochastic resonance based on frequency-information exchange(FIESR),is developed to deal with the adiabatic limit of CSR.The mechanism of FIESR is analyzed in detail by the theory of single-side band modulation(SSB) which is based on phase shift.The information in small-parameter frequency domain is swapped with the information of the high-frequency target signal.Then the amplitude and phase of the target signal are moved to the small-parameter frequency domain.Consequently the target signal can be enhanced and detected by CSR in small-parameter frequency domain.Besides,a necessary plan,narrow band spectrum exchange,is put forward to diminish the influence of the spectrum leakage of FIESR.It is well known that the RFSR is a method of detecting the practical signal with large-parameter frequency.Through rescaling the time interval of the signal and compressing its frequency according to the scale R,the large-parameter frequency is compressed into a small-parameter frequency.The RFSR has a good performance in mechanical incipient fault diagnosis.However,it has a high sampling ratio limitation.The ratio of sampling frequency to target signal frequency is more than 50.T