Noise level estimation in weakly nonlinear slowly time-varying systems
Noise level estimation in weakly nonlinear slowly time-varying systems
复制标题
弱非线性慢时变系统中的噪声水平估计
DOI：
10.1088/0957-0233/19/10/105101
复制
发表时间：
2008
影响因子：
2.4
通讯作者：
J. Dirckx
中科院分区：
文献类型：
--
作者：
J. Aerts;J. Lataire;R. Pintelon;J. Dirckx
最近，提出了一种利用多正弦激励估计弱非线性时不变系统的频率响应、非线性畸变和干扰噪声的方法。该方法已在声驱动系统（如乳胶膜）振动中的非线性畸变测量中得到验证，这是定常系统[1]的一个很好的例子。然而，并不是所有的系统都是完全时不变的，例如生物力学系统。这种时间变化可能被误解为噪声底升高，经典的噪声估计方法给出了错误的结果。提出了两种从测量数据中检索正确噪声信息的改进方法。它们都利用了多重激励。首先，研究表明，当应用于时不变系统（高质量传声器膜）时，改进方法的结果与经典噪声估计方法相同。其次，证明了新方法清楚地给出了时变系统噪声电平的改进估计。作为一个应用实例，给出了耳膜振动响应的计算结果。
Recently, a method using multisine excitation was proposed for estimating the frequency response, the nonlinear distortions and the disturbing noise of weakly nonlinear time-invariant systems. This method has been demonstrated on the measurement of nonlinear distortions in the vibration of acoustically driven systems such as a latex membrane, which is a good example of a time-invariant system [1]. However, not all systems are perfectly time invariant, e.g. biomechanical systems. This time variation can be misinterpreted as an elevated noise floor, and the classical noise estimation method gives a wrong result. Two improved methods to retrieve the correct noise information from the measurements are presented. Both of them make use of multisine excitations. First, it is demonstrated that the improved methods give the same result as the classical noise estimation method when applied to a time-invariant system (high-quality microphone membrane). Next, it is demonstrated that the new methods clearly give an improved estimate of the noise level on time-varying systems. As an application example results for the vibration response of an eardrum are shown.