一个自动控制系统要能常的工作,它必须首 先是一个稳定的系统。也就是说,当系统受界 干扰后,虽然它的原有平衡状态相对稳定状态被破 坏,但在外部干扰去掉后仍有能力自动地在另新 的平衡状态(相对稳定状态下继续工作下去系统的 这一种本能通常叫做統的稳定性。例如常见的电 压自动调节系统中保持电机电压为恒定的能力电机

一、关税与贸易总协定的历史 关贸总协定(the General Agreements on Tariff and Trade,gatt)是一个国际性经济组 织,与国际货币基金组织、世界银行构成调节世界经贸关系的三大支柱

第一节集中式空调系统 第二节半集中式空调系统

The quantity K2 is known as the Kalman gain. It is the optimum gain in the mean squared error sense. Substitute it into the expression for

The estimate of x based on N data points can then be made without reprocessing the first N, points. Their effect can be included simply by starting with pseudo observation which is equal to the estimate based on the first N points having a variance equal to the variance of the estimate based on N The same is true of the variance of the estimate based on N

The two middle terms are zero: fort>lo,n(t) and are uncorrelated becauset) is white(impulse correlation function) For=, n() has a finite effect on x()because n() is white. But the integral of a finite quantity over one point is zero

Solution in the Free Configuration Non-Real-Time Filter Case The applicable condition in this important case is:

System parameters are contained in,(t) and(t) Desired output is generated by taking the signal through the desired operator. The difference between the actual output and the desired output is the error, whose mean squared value we want to minimize We require a stable and realizable system. The error e(t) is given by:

so if t is the current time in a real time situation, we cannot compute ()for which is necessary since w, () is nonzero only for>0. But we showed earlier that

Last time: Ergodic processes An ergodic process is necessarily stationary. Example: Binary process