In time and frequency domain(s)?

Hi there,

I've got a very simple question...

Ex: "First, let's analyze the input signal in time and frequency domains". (*)

Would it be ok grammar-wise if I replaced the plural "domains" with the single form in (*)?

Why do you think the number of search hits for "in time and frequency domain" turned out much larger than for "in time and frequency domainS" ( 653,000 vs 225,000, trivial googling )?