2. Signal processing of biomedical signals a) Describe the most common artifacts observed in the ECG signal and explain if and how those artifacts can be removed. (25%) b) Write the MATLAB code for pre-processing and extracting the envelope from an EMG signal (variable name emg) sampled at 1 KHz. Assume that the signal has also low-frequency movement artifacts up to 20 Hz. Justify your choice of filters. (25%) c) The signal EvokPot is defined in Matlab as a matrix of 150 rows and 500 columns. Each row represent an observation of an evoked potential in the EEG signal of the electrode C3, sampled at 500 Hz. During each epoch, a stimulus was presented after 150 ms from the beginning of the trial. Write the Matlab code for averaging the different observations of the evoked potential and for plotting the resulting signal between the beginning of the trial (marked as -150 ms) and 350 ms after the stimulus. (25%) d) Write the Matlab code for calculating the ratio between the power in the alpha (8-12 Hz) and beta (13-38 Hz) of an EEG (variable eeg) signal sampled at 500 Hz. Justify your choice of filters. (25%)