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Introduction to Signals and Systems
Signal Types by Time and Amplitude
Description
Signals in signal processing are grouped by time behavior, amplitude, and whether they start before or after time zero. These signal classes help students describe and compare signals before they are analyzed or processed.
A continuous-time signal has a value at every instant in time. A discrete-...
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Transcript
信号可分为连续时间信号或离散时间信号、周期信号或非周期信号、模拟信号或数字信号,以及因果信号或非因果信号。
连续时间信号在每一时刻都有取值,而离散时间信号仅在特定时刻有取值。
离散时间信号通常用 x of n 表示,其中 n 为整数,通常用于表示具有本质离散变量的现象。
一个连续时间周期信号(例如正弦波)每 T 秒重复一次,满足周期性条件。任何不满足周期性条件的信号称为非周期信号。
一个周期为正整数 N 的离散时间周期信号,在经历 N 的时间平移后保持不变。离散时间周期信号可以表示为复指数的和,尤其是在使用傅里叶级数进行分析...
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