Why apply resolutons in data words for ARINC 429 bus Data words transported over the ARINC 429 bus are defined and built-in units, ranges, refresh rates, number of significant bits, and resolution. 

Why is it necessary to include resolution? Does resolution really have any significant impact on the signal? I think resolution is just a mere step size for the signal, so why use incremental resolutions, like 0.0000000002? Does this small incremental really make a difference in the data word?
The ARINC 429 Word resolution tells you what value the LSB corresponds to. You can also tell what the resolution should be by looking at the Range and Significant Bits.

It doesn't describe the actual electrical signal.