how to use a low pass filter on a sequence

Hi I have a rr sequence contains different amplitudes .. I want to use a low pass filter do get rid of high amplitudes in the rr sequence who to do it? thanks

Answer 1

[Mahendra]

for example the simplest low pass filter is y(n) = x(n)+x(n-1); {x is the input sequence, y is the filtered sequence}

Y(1) = X(1); 
Y(2:end) = X(2:end)+x(1:end-1);

[Jan]

At least dividing by 2 is useful.

Answer 2

[Jan]

It depends on what the physical nature of the noise is. Maybe a Butterworth filter helps, or a Savitzky-Golay-filter, or a moving average? We cannot decide this reliably only based on the image of the signal. Do you have any further information?

y = movemean(x, 5);

y = sgolayfilt(x, 3, 15);

[b, a] = butter(3, 0.8, 'low');
y      = filter(b, a, x);   % or filtfilt