When I was working as an electronics technician while in college, one of my jobs was to align a complicated stage of our sonar analyzer products. False indications caused by the electronics, not really in the input, we called spurious signals or "spurs". I had a xerox copy of the alignment procedure where a previous technician had written in the margin "I've got spurs that jingle jangle jingle", and sure enough if I twisted the stage out of alignment all sorts of signals popped up on the final display.