Filtering data points and smoothing

Hello I have a filter designed to filter out some noisy datapoints. My filter works well from 100-10000 in x -axis. However, at the beginning of the plot i.e., 1-100, it didn't filter, the filtered data point deviates from the original data points.

Any suggestion is appreciated Best regards, Friet

clear all
clc
close all

M=dlmread('rrawData.txt');

x=M(1:14250,1);
y=(M(1:14250,2));

%Filter design
wn=0.01;
[B,A]=butter(2,wn,'low');

yf=filter(B,A,y);

figure(1)
loglog(x,y,x,yf)
grid on

Answer 1

[Image Analyst]

Then don't use that data. Just replace it with the original data. Or have a smaller filter window for x < 10.

[friet]

If I use the original data in the initial stage, it will be too noisy the initial stage compared with the filtered one.

[Image Analyst]

You only have 20 data points with x < 10. In fact the first 2 or 3 points are wildly different.

If you don't want the points at 10^-12 and 10^-13 smoothed, then where should they be? Tell me where the first point should be if it is not to be in the original location of 10^-12. Tell me where is the preferred location for the point at 5e-14 if it's not right there at 5e-14.

[friet]

Thanks I think i figure it out