Harmonic distortion from nonlinear systems with broadband inputs: applications to lung mechanics.
Harmonic distortion from nonlinear systems with broadband inputs: applications to lung mechanics.
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宽带输入非线性系统的谐波失真：在肺力学中的应用。
DOI：
10.1007/bf02584464
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发表时间：
1995
影响因子：
3.8
通讯作者：
Lutchen,KR
中科院分区：
文献类型：
--
作者：
Zhang,Q;Suki,B;Lutchen,KR
我们提出了一个简单的指标，扩展谐波失真（kd），来表示稀疏伪随机噪声输入（SPRN）下系统非线性的程度。SPRN波形中的频率既不是谐波，也不是其他分量频率的和或差。kk是非输入频率下的输出功率与总输出功率之比的平方根，用百分比表示。我们唤起三个简单的校正，以恢复不完美的SPRN输入下的truekdunder。两个块结构非线性模型（Wiener和Hammerstein）的仿真结果表明，这些修正的必要性和有效性，特别是对Wiener型非线性。通过将kd应用于狗肺的压力-流量数据，我们发现来自肺的非线性谐波相互作用主要来自其组织，最有可能是控制组织刚度的过程。这种非线性，从kd评估，在潮气量较高时更强，在支气管收缩时增强（但程度较低）。我们的结论是，由于kd方法避免了多输入测量和冗长的数据记录的必要性，它可能是有用的跟踪生理系统的非线性的动态变化。
We present a simple index, extended harmonic distortion (kd), to represent the degree of system nonlinearity under sparse pseudorandom noise inputs (SPRN). The frequencies in a SPRN waveform are neither harmonics nor sums or differences of the other component frequencies. Expressed by percentage, thekdis the square root of the ratio of output power at non-input frequencies to the total output power. We evoke three simple corrections to recover the truekdunder imperfect SPRN inputs. Simulations on two block-structured nonlinear models (Wiener and Hammerstein) demonstrate the necessity and effectiveness of these corrections especially for the Wiener-type nonlinearity. By applyingkdto pressure-flow data of dog lungs, we found that the nonlinear harmonic interactions from a lung arise primarily from its tissues most likely the processes governing the tissue stiffness. This nonlinearity, assessed fromkd, is stronger at higher tidal volumes and enhanced (but to a lesser degree) during bronchoconstriction. We conclude that since thekdapproach avoids the necessity for multiple-input measurements and lengthy data records, it may be useful for tracking the dynamic variations in nonlinearities of a physiological system.