what is proper sampling rate in wavelet analysis?

4 次查看（过去 30 天）

Jamais avenir 2013-7-22

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/82744-what-is-proper-sampling-rate-in-wavelet-analysis

there is sth that confuse me about selecting the proper sampling rates.look http://www.mathworks.co.uk/matlabcentral/answers/82676-what-is-the-sampling-frequency-in-wavelet-method for more information.Here I run 3 tests to clarify what I mean. the code is at the bottom. test1: f=[1 3 6],N=300,Fs=10 the result is not very accurate but it is bearable cause the information was not enough. but with changing the N=3000,Fs=100 the result is fine and shows the desired frequencies. Test2: f=[0.1 0.3 0.6],N=300,Fs=10 the result is very accurate.but i am wonder when I change the N=3000,Fs=100 the result is inaccurate.while I remained more information for my signal by N=3000,Fs=100 the last test show what i mean clearly. test3: f=[0.01 0.03 0.06],N=300,Fs=10 the result is Inaccurate.with N=3000,Fs=100 the result is still inaccurate.also with N=30,Fs=1. the result is inaccurate too. cause the signal doesn't have enough information. so the question is "what sampling rate should I select to see frequencies in range of [0 0.1]{like 0.01,0.05}. also further I have frequencies like 0.03,0.5,1.3 in my actual work. so what sampling rate should I select. Kind regards Here is the code. change the 1st two lines with the tests info. if true %tests f=[1 3 6]%f=[0.1 0.3 0.6]%f=[0.01 0.03 0.06] %N=30,300,3000 t=linspace(0,30,300); Fs=ceil(inv(t(2)-t(1))); x=sin(2*pi*t*f(1))+sin(2*pi*t*f(2))+sin(2*pi*t*f(3)); wname = 'morl'; scales = 1:1:128; coefs = cwt(x,scales,wname); freq = scal2frq(scales,wname,1/Fs); figure; plot(freq,coefs) %test1 axis([0 10 -20 20]) %test2 axis([0 1 -20 20]) %test3 axis([0 0.1 -20 20]) end