[SciPy-user] Filtering high frquency noise

[iCy-fLaME]

Assume that the noise power is constant though out your measurement,
and relatively small compare to the signal level, using cubic spline
line interpolation with the weight option might be a fast solution.

The weight is the standard deviation of the noise, this is very easy
to find if you have a bit of signal clear of signals, otherwise it
doesnt take long to guess a close enough value for it.

The advantage of this method is you dont have to worry about the group
delay in with filters, or dispersion to your signal.

Take a look the my data as example, it might help you to choose what to do:
This is the orginal signal as received, 1024 points.
https://warwickultrasound.co.uk/smooth/Org_1024.png

This is the result after a moving average filter:
https://warwickultrasound.co.uk/smooth/Avg_1024.png

This is the result after a badly done FIR filter:
https://warwickultrasound.co.uk/smooth/FIR_1024.png
NB: this is a very bad example, i am sure a carefully choosen FIR
filter can do much better than this.

This is the result after using the cubic spline method i described above:
https://warwickultrasound.co.uk/smooth/Cub_1024.png


Looking at the defference between orginal and filtered signal, i
choose to use the cubic spline method, because the residual seem
uniform enough not to include any signals. i.e. only the noise are
filted out.

--
iCy-fLaME
The body maybe wounded, but it is the mind that hurts.