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MUSE (Multiple sub-Nyquist sampling encoding), was a dot-interlaced digital video compression system that used analog modulation for transmission to deliver 1125-line high definition video signals to the home. Japan had the earliest working HDTV system, which was named Hi-Vision (a contraction of HIgh-definition teleVISION) with design efforts going back to 1979. The country began broadcasting wideband analog HDTV signals in the late 1980s using 1035 active lines interlaced in the standard 2:1 ratio (''1035i'') with 1125-lines total. == History == MUSE, a compression system for Hi-Vision signals, was developed by NHK Science & Technology Research Laboratories in the 1980s, employed 2-dimensional filtering, dot-interlacing, motion-vector compensation and line-sequential color encoding with time compression to 'fold' an original 20 MHz source Hi-Vision signal into a bandwidth of 8.1 MHz. * Japanese broadcast engineers immediately rejected conventional vestigial sideband broadcasting. * It was decided early on that MUSE would be a satellite broadcast format as Japan economically supports satellite broadcasting. Modulation research * Japanese broadcast engineers had studied many kinds of HDTV broadcasts for long time.〔(石田順一・二宮佑一(1982) 「3-1信号方式(3.信号方式と伝送)」, 『テレビジョン学会誌』 36(10), 882-888, 1982-10-20 )〕 At first they thought they had to use SHF, EHF or optic fiber to transmit HDTV by reason of the signal is too broad band and HLO-PAL would be used for terrestrial emission.〔(藤尾孝(1980) 「高品位テレビジョン方式 : 規格, 信号方式と放送方式」, 『テレビジョン学会技術報告』 4(28), 19-24, 1980-11 )〕〔(藤尾孝(1981) 「高品位テレビジョン」, 『テレビジョン学会誌』 35(12), 1016-1023, 1981-12-20 )〕 HLO-PAL is a conventionally constructed composite signal (Y+C, like NTSC and PAL). It uses a Phase Alternating by Line with Half-Line Offset carrier encoding of the wideband/narrowband chroma components. Only the very lowest part of the wideband chroma component overlapped the high-frequency chroma. The narrowband chroma was completely separated from luminance. PAF, with Phase Alternating by Field (like the first NTSC color system trial) was also experimented with, and gave much better decoding results, but NHK abandoned all composite encoding systems. Because of for satellite transmission, Frequency modulation(FM) should be used with power-limitation problem. FM occurs triangular noise. So if sub-carrierrd composite signal is used with FM, demodulated chroma signal has more noise than luminance. Because of this they studied〔(河本太郎 and others(1979) 「IT40-11 BSによる高品位テレビのYC分離伝送実験」, 『テレビジョン学会技術報告』 3(26), 61-66, 1979-11 )〕 and decided〔 to use Y/C component emission for satellite. Once it seemed that FCFE(Frame Conversion Finess Enhanced) , I/P conversion compression system,〔(藤尾孝(1984) 「ICS66-5 高品位テレビジョンシステム」, テレビジョン学会技術報告 8(1), 33-39, 1984-04 )〕 would be chosen, but MUSE was adopted at last.〔(藤尾孝(2006) 「ハイビジョン(HDTV)が世に出るまで:電子画像メディアの感性化,コインの表と裏(<小特集>電子情報通信むかしばなし)」, 『電子情報通信学会誌』 89(8), 728-734, 2006-08-01 )〕 * Separate transmission of Y and C components was explored. The MUSE format that is transmitted today uses separated component signalling. The improvement in picture quality was so great that the original test systems were recalled. * One more power saving tweak was made: Lack of visual response to low frequency noise allows significant reduction in transponder power if the higher video frequencies are emphasized prior to modulation at the transmitter and de-emphasized at the receiver. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Multiple sub-Nyquist sampling encoding」の詳細全文を読む スポンサード リンク
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