How can i filter an EEG signal?

I have generated an EEG signal in MATLAB.Then in have added random noise to it,n then filtered it using the code as under.But i am getting an error.Can anyone help me to remove it ?

 fs = 512
 T = 1/fs;
 N =length(EEGsig); ls = size(EEGsig);
 tx =[0:length(EEGsig)-1]/fs;
 fx = fs*(0:N/2-1)/N;
 x=  EEGsig;    
 sd = 0.1;                                       
 normal_noise = sd*randn(1, N);
 noisy_EEGsig = x + normal_noise;
 figure();    
 subplot(4,1,1);
 grid on;  
    
 plot(tx, x);
 xlabel('Time [s]');                                                        
 ylabel('Amplitude');
 title('Original signal');
 subplot(4,1,2);
 grid on;  
 plot(tx,normal_noise);
 xlabel('Time [s]');
 ylabel('Amplitude');
 title('Noise');
 subplot(4,1,3);
 grid on;
 plot(tx, noisy_EEGsig);
 xlabel('Time [s]');
 ylabel('Amplitude');
 title('Original signal + Noise'); 
 subplot(4,1,4);
 d = designfilt('bandstopiir', 'FilterOrder', 2, 'HalfPowerFrequency1', 59, 'HalfPowerFrequency2', 61, 'DesignMethod', 'butter', 'SampleRate', fs);
 fvtool(d,'fs',fs)  
 buttLoop = filtfilt(d, noisy_EEGsig);
 plot(t, noisy_EEGsig,t,buttLoop)
 ylabel('Voltage (V)')
 xlabel('Time (s)')
 title('filtered signal')
 legend('Unfiltered','Filtered')
 grid

The error i am getting is :

"Undefined function 'designfilt' for input arguments of type 'char'."

[aida]

your error in this line (9.noisy_EEGsig = x + normal_noise) and error because of sum different matrix with each other and the correct on is noisy_EEGsig = tx + normal_noise

Answer 1

[Star Strider]

Three possibilities:

1. You do not have the Signal Processing Toolbox (that has the designfilt function);

2. Your MATLAB and Signal Processing Toolbox versions are prior to R2014a when designfilt was added;

3. You have an appropriate version of the Signal Processing Toolbox, and need to run these commands (from your Command Window or a script) to restore the correct paths:

restoredefaultpath 
rehash toolboxcache

Note that no frequency-selective filter will completely eliminate broad-band noise, and a bandstop filter of the sort you want to implement will only eliminate 60 Hz mains frequency noise.