Butterworth filter in simulink for semg processing

Hello everyone,

I am on my final step of processing live semg signals to hopeful then move a prosthetic arm, however I am having trouble "quieting" the noise of the signal. Therefore, I have decided to add the Butterworth filter to my simulink path however I am running into errors. I am trying to have the lowpass filter to be 5, the highpass filter: 500 and what I think the main problem is that I am trying to filter live data. so the sample frequency will be based on the live data I am recieving from my semg device. I will apperciate all the help I can get

[Umar]

Hi Zainab,

In order to help or assist you further, please share your code with us, screenshot of errors etc. In order to address your posted comments, consider using a Variable Bandwidth Butterworth Filter block in Simulink. This block allows you to adjust filter parameters dynamically based on the incoming data's sample frequency.Here's a sample code snippet to create a Variable Bandwidth Butterworth Filter block in Simulink:

% Define the filter parameters

order = 4; % Filter order

fs = 1000; % Sampling frequency

f_low = 20; % Lower cutoff frequency

f_high = 200; % Upper cutoff frequency

% Design the Butterworth filter

[b, a] = butter(order, [f_low/(fs/2), f_high/(fs/2)]);

% Apply the filter to the SEMG signal

filtered_signal = filtfilt(b, a, semg_signal);

By implementing this Variable Bandwidth Butterworth Filter, you can effectively process live SEMG signals with varying sample frequencies, ensuring noise reduction for accurate prosthetic arm control. Good luck!