An introduction is given to papers submitted to a November 1991 meeting of the International Radio Consultative Committee (CCIR) Task Group on high-definition television (HDTV). The purpose of the digital HDTV broadcasting documents is to respond to questions posed in the CCIR. Key issues are harmonization of high resolution imaging standards among applications, compression algorithms, source coding, channel coding, modulation techniques, and spectrum strategy. Since the information provided to the CCIR did not contain block diagrams of the proposed systems, block diagrams of a typical encoder and decoder are provided. The diagrams are not precisely descriptive of any of the proposed systems, but are generally descriptive of all of them. >