如何在Python中编写采样信号的低通滤波器？

问题描述

对不起，可能是微不足道的问题，但我是信号处理新手，我没有找到很好的解释python代码。所以我会很高兴得到对dummy的解释：）

我有一些信号每1nsec（1e-9秒）被取样，并且有1e4点。
我需要从这个信号过滤高频率。假设我需要过滤高于10MHz的频率。
我希望对于频率低于截止频率的信号将不变。这意味着对于低于截止频率的频率，滤波器的增益将为1。
我希望能够指定过滤顺序。我的意思是，阶数滤波器在截止频率后有20db / decade的斜率（功率滚降），二阶滤波器在截止频率后有40db / dec的斜率等等。
代码的高性能是重要的。

非常感谢您的帮助。
Alex。

解决方案

您好像有两个问题：

1. 如何设计一个10MHz截止频率和任意滤波器顺序的低通滤波器？


2. 如何在Python中实现滤波器？过滤器的设计超出了堆栈溢出的范围 - 这是一个DSP问题，而不是一个编程问题。任何DSP教科书都可以使用滤波器设计 - 进入您的图书馆。我喜欢Proakis和Manolakis的数字信号处理技术。 （Ifeachor和Jervis的数字信号处理也不错）。
   
   

   如果你一定要有这个东西，试试，展示了如何设计巴特沃斯低通过滤器使用 scipy 。

   
   
   

   至于在Python中实现过滤器， scipy 有一个，它将FIR或IIR滤波器应用于一维信号。


   Sorry for question that may be trivial, but I am new in signal processing, and I didn't find python code with good explanation. So I will be glad to get explanation for dummy :)

   I have some signal that sampled each 1 nsec (1e-9 sec) and have, let say, 1e4 points.I need to filter high frequencies from this signal. Let say I need to filter frequencies higher than 10MHz.I want that for frequencies lower than cutoff frequency signal will be passed unchanged. It means gain of the filter will be 1 for frequencies lower than cutoff frequency.I would like to be able to specify filter order. I mean, fitsr order filter have 20 db/decade slope (power rolloff) after cutoff frequency, second order filter have 40 db/dec slope after cutoff frequency and so on.High perfomance of code is importent.

   Thank you very much for help.Alex.

   解决方案

   You appear to have two questions:

   1. How do I design a lowpass filter with a 10MHz cutoff frequency and an arbitrary filter order?
   2. How do I realise that filter in Python?

   Filter design is beyond the scope of Stack Overflow - that's a DSP problem, not a programming problem. Filter design is covered by any DSP textbook - go to your library. I like Proakis and Manolakis' Digital Signal Processing. (Ifeachor and Jervis' Digital Signal Processing isn't bad either.)

   If you must have teh coeds, try this blog post, which shows how to design a Butterworth lowpass filter with scipy.

   As for implementation of the filter in Python, scipy has a lfilter() function which applies a FIR or IIR filter to a signal in one dimension.

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