In facsimile, a frequency modulationsystem where one frequency represents picture black and another frequency represents picture white[?]. Frequencies between these two limits may represent shades of gray
An intentional frequency change used for modulation purposes
... is 19.9/km² (51.6/mi²). There are 205 housing units at an average density of 8.7/km² (22.6/mi²). The racial makeup of the town is 46.37% White, ...