Smooth data over a certain frequency?

My data, traces over time, contain noise that seems to happen at a frequency of 3 to 4 Hz. What is the best way to smooth out this type of noise at a specific frequency without losing peak data?

Answer 1

[Star Strider]

Without having your signal, I cannot provide specific code. To eliminate frequency-limited noise, I would use a bandstop filter with a stopband of 3 Hz to 4 Hz.

There are several ways to design filters in MATLAB, including dfilt and designfilt. My filter design procedure for IIR filters is here: How to design a lowpass filter for ocean wave data in Matlab? See the documentation for all the functions mentioned for an explanation of their options.