The repository is here https://gitlab.com/Jochen/jochen.gitlab.io

(you can find it under code in the navigation bar). The post is a jupyter notebook which can be found under content/blog

Regarding dummy arrays, you can just generate random arrays of complex values, that should normally not cause issues (although obviously the filter does not converge to anything). The size I used for the demo is (2, 200 000), i.e. 2 polarisations and 100 000 symbols 2 times oversampled