About MASH and single loop multibit delta-sigma modulators

In ΔΣ fractional-N frequency synthesizer, MASH or single loop multibit Δ-Σ modulators are usesd. The structure of MASH is obvious,which is some accumulators , adders and registers, my question is how to realize it? Using transistors to build it or using verilog to generate it?
And how to realize single loop multibit Δ-Σ modulators?
Thanks!