You can use smoothdata as a quick-and-dirty low pass filter:
% sine wave with noise example
y1 = sin(linspace(0,20*pi,200));
y1 = y1 + rand(1,200);
y2 = smoothdata(y1, 'movmean', 5); % through lp filter
% square wave example
y3 = repmat([1 0], 10, 10);
y3 = y3(:);
y4 = smoothdata(y3, 'movmean', 5); % through lp filter
tiledlayout(2,2);
nexttile(1);
plot(y1);
ax = gca;
ax.YLim = [-2 2];
nexttile(3);
plot(y2);
ax = gca;
ax.YLim = [-2 2];
nexttile(2);
plot(y3);
ax = gca;
ax.YLim = [-2 2];
nexttile(4);
plot(y4);
ax = gca;
ax.YLim = [-2 2];
You can increase the 3rd argument in smoothdata to get more aggressive filtering.
