I am trying to generate a clock signal with random noise, but not using complicated VCO models in Cadence Spectre.

One possible way I think is to use the vsource in analogLib with "prbs" type, and specify the bit file with "...0101..." pattern. So that, I can put the noise for the pattern as provided by the vsource model.

But I don't know how to construct the bit file. Could someone please explain how to do it or direct me to some reference?