Is there a code to get multiple velocity time histories equivalent to a single power spectrum?

I am working on generating seimic noise numerically. I have a power spectrum (power spectral density). I want to generate velocity time histories compatible to the power spectrum. Is there any code for that?

There may very well be, I googled ‘python seismic data processing’ and got lots of results: Seismic-py, ObsPy, etc. I suggest you have try yourself and see what fits your needs or not.