问题
Is there an easy way to apply a low-pass or high-pass filter to an array in MATLAB? I'm a bit overwhelmed by MATLAB's power (or the complexity of mathematics?) and need an easy function or some guidance as I couldn't figure it out from the documentation or searching the web.
回答1:
Look at the filter function.
If you just need a 1-pole low-pass filter, it's
xfilt = filter(a, [1 a-1], x);
where a = T/τ, T = the time between samples, and τ (tau) is the filter time constant.
Here's the corresponding high-pass filter:
xfilt = filter([1-a a-1],[1 a-1], x);
If you need to design a filter, and have a license for the Signal Processing Toolbox, there's a bunch of functions, look at fvtool and fdatool.
回答2:
You can design a lowpass Butterworth filter in runtime, using butter() function, and then apply that to the signal.
fc = 300; % Cut off frequency
fs = 1000; % Sampling rate
[b,a] = butter(6,fc/(fs/2)); % Butterworth filter of order 6
x = filter(b,a,signal); % Will be the filtered signal
Highpass and bandpass filters are also possible with this method. See https://www.mathworks.com/help/signal/ref/butter.html
来源：https://stackoverflow.com/questions/1783633/how-to-apply-a-low-pass-or-high-pass-filter-to-an-array-in-matlab