Reputation: 49
Does downsampling using stream.resample () in Python introduce aliasing effect? I want to investigate a signal below 4 Hz. It has the original sampling rate of 100 Hz but I need to downsample it as much as possible. If I use In Python st.resample() based on the documentation (https://docs.obspy.org/packages/autogen/obspy.core.stream.Stream.resample.html) it does the resampling using a Fourier method. If I downsample to 8 Hz:
st.resample (8)
Will I have an aliasing effect considering that my interest frequency is below 4 Hz?
What if I set the no_filter to False:
st.resample (8, no_filter=False)
Upvotes: 0
Views: 435
Reputation: 17975
no_filter=False
only reduces high frequency components, which only smooth the signal, it doesn't matter in terms of aliasing, you can think of it as smoothing after the resampling.Upvotes: 1