翻译：Page 76
The stability of a continuous ordiscrete-time system is determined by its response to input or disturbance.Intuitively, a stable system is one that remains at rest (or in equilibrium)unless excited by an external source and returns to rest if all excitations areremoved. The output will pass through a transient phase and settle down to asteady-state response that will be of the same form as, or bounded by, theinput. If we apply the same input to an unstable system, the output will neversettle down to a steady-state phase; it will increase in an unbounded manner,usually exponentially or with oscillation of increasing amplitude.
    连续或离散系统的稳定性由其对输入或者干扰的响应决定。直观地说，如果一个系统是稳定的，则其停留在稳态（或者平衡点），除非是受到外部激励，且当外部激励去除后，输出又回到稳态点。输出经过瞬态阶段后将回到与输入有相同形式的稳态或者是在输入的附近。如果我们将同样的输入作用于不稳定的系统，其输出将不会回到稳态，而是以无界的方式增长，通常其幅值是指数增长或者振荡增长。An acceptable system must at minimumsatisfy the three basic criteria of stability, accuracy, and a satisfactorytransient response. These three criteria are implied in the statement that anacceptable system must have a satisfactory time response to specified inputsand disturbances. So although we work in the Laplace and frequency domains forconvenience, we must be able to relate these two domains, at leastqualitatively, to the time domain.
一个可接受的系统必须至少满足：稳定性、精度和满意的瞬态响应这三个指标。在陈述：“一个可接受的系统对指定输入和扰动必须有满意的时域响应”已经包含了这三个指标的含义。因此尽管我们为了方便工作在拉氏域或者频率域，我们必须与时间域（至少是定性的）相联系。
In fact, the Laplace domain can providesinformation about the transient response of both stable and unstable systemsand about the steady-state response of stable systems. This article isconcerned with relating the Laplace domain to the time response with emphasison the transient response, and with establishing specific criteria in theLaplace domain for system stability. Accuracy will be treated in the nestarticle, and the frequency response in the subsequent units。
实际上，拉氏域既能提供稳定和不稳定系统的暂态响应信息，也能提供稳定系统的稳态响应的信息。本文讨论拉氏域和时间响应的关系，并重点强调暂态响应，和在拉氏域中建立系统稳定性的判剧。精度将在下一篇文章中讨论，频率响应在以后的单元中讨论。
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Lumped parameterand distributed parameter syste***umped parameter systems are those for whichphysical characteristics are assumed to be concentrated in one or more ”lumps”and thus independent of any spatial distribution. in effect, bodies are assumedrigid and treated as point massed; springs are massless and electrical leadsresistanceless, or suitable corrections are made to the system mass orresistance; temperatures are uniform; etc. In distributed parameter systems,the continuous spatial distribution of a physical characteristic is taken in toaccount. Bodies are elastic, springs have a distributed mass, electrical leadshave a distribute resistance, and temperatures vary across a body. Lumpedparameter systems are described by ordinary differential equation; whiledistributed parameter systems are described by partial differential equations.
集中参数和分散参数系统：集中参数系统是其物理性质被假设集中在一块或多块，从而与任何空间分布无关的系统。在作用上，物体被假设为刚性的，被作为质点处理；弹簧是没有质量的，电线是没有电阻的，或者对系统质量或电阻进行适当的补偿；温度在各部分是一致的，等等。在分布参数系统中，要考虑到物理特性的连续空间分布。物体是有弹性的，弹簧是有分布质量的，电线具有分布电阻，温度在物体各处是不同的。集中参数系统由常微分方程描述，而分布参数系统由偏微分方程描述。