CEMA Publishes VSB Digital Standard With Enhanced On-Screen Display Capabilities

The Consumer Electronics Association (CEMA) has published a voluntary standard (EIA-761) for interface between digital set-top boxes and digital television DTV) receivers using the ATSC digital modulation system, Vestigial SideBand (VSB). The DTV Remodulator Specification with Enhanced On-Screen Display (OSD) Capability standard applies to the connection between devices such as digital cable decoder, a satellite receiver, a digital VCR or a computer, and a DTV receiver.The interface can be used to translate Quadrature Ampliture Modulation (QAM), used by some in the cable industry, into VSB, the terrestrial broadcast transmission standard accepted by the Advanced Television Systems Committee (ATSC) and mandated by the Federal Communications Commission (FCC) for use with DTV.This standard, recently adopted by the CEMA R-4 Video Systems Committee, addresses on-screen display mechanisms for greater interoperability with digital cable and digital VCR applications in both the 8-VSB and I6-VSB modes of operation. Specifically, it addresses required RF output specifications, OSD capabilities, and the capability profiles for a DTV remodulator. Recommendations concerning input to the remodulator are also included. EIA-761 is based on the previously approved EIA-762 standard. EIA-762 only covered 8-VSB and did not include provisions for OSD. The CEMA committee has already adopted a recommended practice, CEB5 that details a ""monitor mode"" that is accessed like the ""auxiliary"" input on analog TV receivers and involves only minor DTV software changes. In the monitor mode, the receiver ignores channel frequency data contained in the program system information protocol (PSTP) as it may not be correct when coming from a secondary source such as a digital VCR.