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The Grand Alliance (GA) was a consortium created in 1993 at the behest of the Federal Communications Commission (FCC) to develop the American HDTV specification, with the aim of pooling the best work from different companies. A consortium is an association of two or more individuals companies organizations or governments (or any combination of these entities with the objective of participating High-definition television (HDTV is a Digital television Broadcasting system with higher resolution than traditional television systems (standard-definition It consisted of AT&T, General Instrument Corporation, Massachusetts Institute of Technology, Philips Consumer Electronics, David Sarnoff Research Center, Thomson Consumer Electronics, and Zenith Electronics Corporation. Before proposing a merge request please see Talk and see if the merger you propose has recently been made and General Instrument (GI was an Electronics Manufacturer based in Chicago, IL specializing in Semiconductors and Cable television Koninklijke Philips Electronics NV ( Royal Philips Electronics Inc. Sarnoff Corporation, with headquarters in West Windsor New Jersey, is the former RCA Laboratories Thomson SA (,) formerly known as Thomson Multimedia is an international provider of solutions for the creation management delivery and access of video for the Zenith Electronics Corporation is a former American manufacturer of Televisions headquartered in Lincolnshire Illinois The Grand Alliance DTV system is the basis for the ATSC standard.

Recognizing that earlier proposed systems demonstrated particular strengths in the Advisory Committee on Advanced Television Service (ACATS) testing and evaluation process, the Grand Alliance system was proposed to combine the advantages of all of the previously proposed terrestrial digital HDTV systems. At the time of its inception, the Grand Alliance HDTV system was specified to include:

Audio and transmission systems had not been decided at the time of the GA agreement. Five channel audio was specified, but a decision among the Dolby AC-3, multi-channel MPEG-1 Layer II (MP2) audio, and MIT "AC" systems had not yet been made. Dolby Digital is the marketing name for a series of lossy audio compression technologies developed by Dolby MPEG-1 Audio Layer II ( MP2, sometimes incorrectly called Musicam) is an Audio codec defined by ISO/IEC 11172-3 Candidate transmission approaches included QAM, Spectrally-Shaped QAM, 6 VSB (with trellis code) and 4/2 VSB. Single-sideband modulation ( SSB) is a refinement of Amplitude modulation that more efficiently uses electrical power and bandwidth. In Telecommunication, trellis modulation (also known as trellis coded modulation, or simply TCM) is a modulation scheme which allows highly efficient COFDM had been proposed by third parties, but was rejected as not being mature, and not offering fringe-area coverage equivalent to analog transmission. Orthogonal frequency-division multiplexing ( OFDM) — essentially identical to Coded OFDM ( COFDM) and Discrete multi-tone modulation ( TV DX and FM DX are two terms customarily grouped together that refer to long-distance reception of TV and FM Radio stations respectively A thorough analysis of service area, interference characteristics, transmission robustness and system attributes would be performed to determine the "best approach. "

In the end, 1080- and 720-line resolutions were implemented, together with 8-VSB modulation and Dolby AC-3 audio. 8VSB is the 8-level Vestigial sideband modulation method adopted for terrestrial broadcast of the ATSC digital television standard in the United States, However, the selection of transmission and audio systems was not without controversy. The choice of 8-VSB was later criticised by several groups as being inferior to COFDM under conditions of multipath. In Wireless Telecommunications multipath is the propagation phenomenon that results in Radio signals reaching the receiving Improvements in receiver designs would later render this apparently moot. With MP2 originally faltering during GA testing, the GA issued a statement finding the MP2 system to be "essentially equivalent" to Dolby, but only after the Dolby selection had been made. Later, a story emerged that MIT had entered into an agreement with Dolby whereupon the university would be awarded a large sum if the MP2 system was rejected. Following a five-year lawsuit for breach of contract, MIT and its GA representative received a total of $30 million from Dolby, after the litigants reached a last-minute out-of-court settlement.

Grand Alliance Chronology

References

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