this is my first time extracting eeg signal.for practising only beta wave is taken.after running my code there doesn't show any curve though no error is found.M1 is declared as variable help me to find the problem

load S001R01_edfm.mat;% loading data
Ts=2;% sampling period
Fs=500;%sampling frequency
[N,nu]=size(M1);%obtain size of data
t=(1:N)*Ts;%generates time vector
%%Raw Signal Analysis
figure()
title('EEG Wave Patterns')
subplot (2,1,1),plot(t,M1)  
grid on;
    xlabel('Time(s)')
    ylabel('Amplitude')
    title('Raw EEG Signal')
    xlim([0 (1600)])

%BETA BANDPASS FILTER (12-30)

Fs = 500; % Sampling Frequency

Fstop1 = 11.5;            % First Stopband Frequency
Fpass1 = 12;              % First Passband Frequency
Fpass2 = 30;              % Second Passband Frequency
Fstop2 = 30.5;            % Second Stopband Frequency
Dstop1 = 0.0001;          % First Stopband Attenuation
Dpass = 0.057501127785; % Passband Ripple
Dstop2 = 0.0001;          % Second Stopband Attenuation
dens   = 20;              % Density Factor

% Calculate the order from the parameters using FIRPMORD.
[N, Fo, Ao, W] = firpmord([Fstop1 Fpass1 Fpass2 Fstop2]/(Fs/2), [0 1 ...
                          0], [Dstop1 Dpass Dstop2]);

% Calculate the coefficients using the FIRPM function
b4   = firpm(N, Fo, Ao, W, {dens});
Hd4 = dfilt.dffir(b4);
x4=filter(Hd4,M1);
subplot(2,1,2), plot(t,x4) 
    grid on;
    xlabel('Time(s)')
    ylabel('Amplitude')
    title('BETA Waves')
    xlim([0 (1600)])
title('waveform for BETA band')

Answer 1

[Walter Roberson]

Your code

t=(1:N)*Ts;%generates time vector

is not right: it does not take into account the sampling frequency. More likely to be right would be

t = (0:N-1) / Fs;

[tahia chowdhury]

i change the code as you said so.but here, same problem is again showed

[Walter Roberson]

Unfortunately we do not have your data to test with.

[tahia chowdhury]

my data

Answer 2

[vijaya kumar]

try this

t=(0:nu-1)/Fs;