Signal transmission standards describe the specific characteristics of the broadcast television signal radiated within the allocated spectrum. These standards may be summarized as follows:

• Definitions of fundamental functions involved in producing the radiated signal format, including the relative carrier and subcarrier frequencies and tolerances as well as modulation, sideband spectrum, and radio-frequency envelope parameters

• Transmission standards describing the salient baseband signal values relating the visual psychophysical properties of luminance and chrominance values, described in either the time or frequency domains

• Synchronization and timing signal parameters, both absolute and relative

• Specific test and monitoring signals and facilities

• Relevant mathematical relationships describing the individual modulation signal components

The details of these signal transmission standards are contained within standards documents for the countries and/or regions served. For conventional (analog) broadcasting, the signal formats are NTSC, PAL, and SECAM. For digital television, the two principal transmission systems are the ATSC DTV system and the European DVB system.

Having established the requirements for television transmission, the appropriate hardware issues then come into play. In this section, a number of technologies are examined that are used to deliver both analog and digital signals to consumers via over-the-air broadcasting. Considerable advancements in both solid-state- and vacuum-tube-based devices and systems have provided...