关于信号处理函数
可使用信号处理函数来分析、解释和操作模拟信号与数字信号。
以下规则适用于信号处理函数：
• 频率的测量单位通常为“赫兹-秒”，即，以采样频率的分数形式表示。因此频率自变量通常介于 0 和 0.5 之间。
• 很多信号处理函数都基于离散傅立叶变换，且使用
dft 函数。为获得最大的灵活性，输入数组的长度未被限定为 2 的方幂。当长输入矢量的长度仅为一或两个因子时，
dft 程序会变慢。在长度为较大质数的特殊情况下，
dft 函数只能将定义变换的指数和加在一起。在这种情况下，长度的微小变换就可能会造成计算时间发生很大变化。
信号处理参考文献
信号处理函数的实现方法和算法在以下所列书籍中进行了介绍：
• Bruce L. Bowerman and Richard T. O'Connell, Time Series Forecasting, Duxbury Press (1987)
• Ronald N. Bracewell, The Hartley Transform, Oxford University Press (1986)
• Leon Cohen, Time-Frequency Analysis, Prentice-Hall (1995)
• Rafael C. Gonzalez and Paul Wintz, Digital Image Processing, Addison-Wesley (1977)
• C. W. J. Granger and Paul Newbold, Forecasting Economic Time Series, Academic Press, Inc. (1986)
• Hwei P. Hsu, Schaum's Outline of Theory and Programming of Signals and Systems, McGraw-Hill, Inc.(1995)
• S. Lawrence Marple, Jr., Digital Spectral Analysis with Applications, Prentice-Hall (1987)
• Sophocles J. Orfanidis, Optimum Signal Processing, 2d ed, Macmillan (1988)
• T. W. Parks and C. S. Burrus, Digital Filter Design, Wiley-Interscience (1987)
• Alan V. Oppenheim and Ronald W. Schafer, Discrete-Time Signal Processing, Prentice Hall (1989)
• Donald B. Percival and Andrew T. Walden, Spectral Analysis of Physical Applications, Cambridge University Press (1993)
• William H. Press, Brian P. Flannery, Saul A. Teukolsky, and William T. Vetterling, Numerical Recipes in C, Cambridge University Press (1988)
• Programs for Digital Signal Processing, IEEE Press (1979)
• Lawrence R. Rabiner and Bernard Gold, Theory and Application of Digital Signal Processing, Prentice-Hall, Inc. (1975)
• Mary Beth Ruskai et al., eds., Wavelets and Their Applications, Jones and Bartlett Publishers (1992)
• Samuel Stearns and Ruth A. David, Signal Processing Algorithms, Prentice-Hall, Inc. (1988)