How to Correct Signal Waveform (may use some filter)

Hello, I would like to ask is there a way to process below data so that, when y goes from -1 to 1 (or from 1 to -1), there are no small dips near 1 (or -1). The force applied to generate such data has squre waveform. But my data waveform is distorted.

I have tried using lowpass(), but the dips are still there. Data and figure are attached.

Manny thanks and best regards,

Ryanne

[Runzi Hao]

Also I hope the near 1 (or near -1) signals before the dips can be increased to 1 (or -1).

The sampling rate is 1e11 Hz. Data in first column is in nanoseconds.

Answer 1

[Chunru]

You can try to use a low pass filter.

websave("data.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1372834/ask_matlab_community.mat")

ans = '/users/mss.system.ENlxcn/data.mat'

load data
% design a low pass filter
d = designfilt("lowpassfir", PassbandFrequency=0.04, StopbandFrequency=0.12, ...
    PassbandRipple=1, StopbandAttenuation=60);

x = filtfilt(d, dataAsk(:,2));

plot(dataAsk(:,1), dataAsk(:, 2))
hold on;
plot(dataAsk(:,1), x)

[Runzi Hao]

Cool! It works well and thank you so much for the solution!