human action,
human activity,
deed,
act a legal document signed and sealed and delivered to effect a transfer of property and to show the legal right to possess it; "he signed the deed"; "he kept the title to his car in the glove compartment"
trouble an effort that is inconvenient; "I went to a lot of trouble"; "he won without any trouble"; "had difficulty walking"; "finished the test only with great difficulty"
clutter unwanted echoes that interfere with the observation of signals on a radar screen
background signal,
background (computer science) the area of the screen in graphical user interfaces against which icons and windows appear
crosstalk,
xt the presence of an unwanted signal via an accidental coupling
fadeout a gradual temporary loss of a transmitted signal due to electrical disturbances