Gives methods of measurement for television broadcast receivers under conditions in which the signal presented to the receiver is not in accordance with the specifications for broadcast signals adopted by the CCIR. Such nonstandard signals may be produced by video tape recorders, video disc players and television games, among other sources. Specifies methods of measurement for those characteristics of broadcast television receivers using existing technology which have been found, by experience of the nature of signals produced by existing types of ancillary equipment and systems, to be significant in determining their mutual compatibility.