测控技术与仪器专业英语教程(第2版)课后答案

第一章

1.简谐信号是最简单和最重要的周期信号。任意一个周期信号可以用简谐信号来表达，两者之间联系的桥梁是傅里叶级数，所以傅里叶级数是周期信号分析的理论基础。

翻译：Harmonic signal is the simplest and the most important periodic signal. Any one of the periodic signal can use harmonic signal to express, contact between the bridge is Fourier series, so Fourier series is periodic signal analysis of the theoretical basis.

2.一个在时域上显得很复杂的信号，将其变换或映射到频域（包括s和z域），就能够分解为非常简单的基本信号形式，进行分析和求解。

翻译：A time domain appear very complex signal, its transformation or mapping to the frequency domain (including s and z domain), can be decomposed to A very simple basic signal form, carries on the analysis and solution.

第二章

1.信号不是周期性出现，而只是持续一段时间，不再重复出现，如过渡过程、爆炸产生的冲击波、起落架着陆时的信号等，把这一类信号看成为非周期信号。分析非周期信号的思路是：在时域上，当周期A，周期信号变成为非周期信号：在频域上，周期信号的频谱在A时的极限，变为非周期信号的频谱，即傅里叶变换。

翻译：Signals are not periodic appear, but only for a period of time, and shall not repeat appear, such as the transition process from an explosion, the shock wave, landing gear landing signal, this kind of signal see as a periodic signal. Analysis of the thinking of the periodic signal in time domain, when A cycle, cycle signal into non periodic signal: in the frequency domain, the signal spectrum in A cycle of limit, A non periodic signal spectrum, namely Fourier transform.

2.信号在时域压缩α倍（α>0）时，则在频域中频带加宽，幅值压缩1/α倍；反之信号在时域扩展时（α<1），在频域中将引起频带变窄，但幅值增高。

翻译：Signal in time domain compression αtimes (α> 0), the band in frequency domain widened, amplitude compression 1 / αtimes; And signal in time domain extension (α< 1), in the frequency domain will cause narrow band, but increased amplitude.

第四章

1.随机信号是不能用精确的数学关系式描述的信号，但它的变动服从统计规律，可以用概率统计特性来描述。对随机信号按时间历程所做的各次长时间观测记录称为样本函数。

翻译：Random signal is not a precise mathematical relation description of the signal, but it changes to obey statistical rule, can use probability statistics characteristic to describe. To random signal according to the time course of the long time observation record called sample function.

2.随机信号的时域和频域特性可以用统计方法进行研究，其幅值特性用信号的均值、均方值和概率密度函数表示。信号的时域特性也可以用自相关函数描述，频域特性用功率谱密度函数描述。

翻译：Random signal of time domain and frequency domain properties can use statistical methods, the characteristics of the signal amplitude with the mean and the mean square value and probability density function said. The signal characteristics in time domain, also can use the autocorrelation function description, the frequency domain characteristics with power spectral density function description.

第五章

1.当被测量不随时间变化或变化缓慢时，输出y与x之间的关系成为静态特性；当被测量随时间迅速变化时，输出y与x之间的关系称为动态特性。

翻译：When measuring don't change over time or changes slowly, output y and the relationship