The RMS value needs to be calculated for a vector. Since the RMS =s the square root of the mean of the squared values of that vector, one option is to use the movmean function to create a moving estimate of the RMS value.
Try this:
t = linspace(0, 10, 1000); % Time Vector
v = 1.2+sin(2*pi*t*100)+randn(1,1000)*0.1; % EMG Vector
WinLen = 10; % Window Length For RMS Calculation
rmsv = sqrt(movmean(v.^2, 10)); % RMS Value Over ‘WinLen’ Samples
figure
plot(t, v)
hold on
plot(t, rmsv, '-r', 'LineWidth',1.5)
hold off
grid
legend('EMG',sprintf('RMS (Window Length = %d)',WinLen), 'Location','best')
Experiment to get the result you want.
