CEEFAX: An investigation of interference from teletext data signals into the sound circuits of domestic television receivers

Experimental work conducted to determine the circumstances under which a television sound signal, as received in domestic television receivers in Great Britain, is subject to 'data buzz' interference was described. This type of interference has been observed when receiving System 1 television transmission, with teletext data occupying lines 17, 18, 330, and 331 in the field-blanking interval. Tests performed on a number of domestic television receivers to assess their susceptibility to it were also reported.