1680s, "one who scrambles," in any sense; 1902, "that which scrambles;" agent noun from scramble (v.). By 1950 specifically of an electronic device to make sounds unintelligible.
Entries linking to scrambler
scramble v.
1580s (intransitive), "make one's way by clambering, etc., struggle or wriggle along," also "strive with others or jostle and grasp rudely for a share or for mastery;" a word of obscure origin, perhaps a nasalized variant of scrabble (v.) "to struggle; to scrape quickly." OED points to dialectal scramb "pull together with the hands," a variant of scramp, which is probably a nasalized form of scrape.
Mrs. Goddard was the mistress of a school, ... a real, honest, old fashioned boarding-school, where a reasonable quantity of accomplishments were sold at a reasonable price, and where girls might be sent to be out of the way, and scramble themselves into a little education, without any danger of coming back prodigies. [Jane Austen, "Emma"]
The transitive sense of "to stir or toss together randomly, cause to move confusedly" is from 1822. The transitive sense, in reference to radio signals, telephone voices, etc., "to make unintelligible," is attested from 1927, hence generally "to jumble, muddle." In U.S. football, in reference to a quarterback avoiding tacklers, by 1964. Related: Scrambled; scrambling. Scrambled eggs, broken into a pan, mixed with butter, salt, pepper, etc., and cooked slowly,is by 1843.