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D-和D2MAC/packet是在C-MAC/Packet基础上发展起来、原本是想用于电缆电视系统的。欧广联最近公布了用于直播卫星的D2-MAC/packet传送技术标准。C-MAC/packet制的信息可以在宽带电缆通道(至少10.5MHz)中以D-MAC/packet的残留边带调幅方式传送。而在窄带电缆通道(至少7MHz)中也可将C-MAC/packet的码转换成D2-MAC/packet传送,不过得削减一半声音/数据信息,而且由于残留边带的带宽限制,图像的水平分解力也有所降低。与C-方式不同,D-和D2-MAC/packet中数字的声音/数据群不是二进制,而是双值二进制编码,然后将这个双值二进制信号插入到基带信号中去共同调制载波。就视频规格本身(MAC)来说,这三种MAC/packet之间没有区别,但就D2来说,使今后有可能扩大图像宽高比的方法,受到不能缩短数据串的限制。联邦德国政府和法国政府于1985年6月达成协议,同意在直播卫星TV-SAT和TDF-1中直接使用D2-MAC/packet,而不经过PAL/SECAM的中间过渡。因此D2-MAC/packet的解码器必须在1986年底之前提供使用,这第一批解码器还不能完全符合欧广联的技术标准,其中与法国约定的起码的技术标准见文后附录(未译出,见原文)。
D- and D2MAC / packet were developed on the basis of C-MAC / Packet originally intended for cable television systems. The European Broadcasting Union recently announced the D2-MAC / packet transmission technology standard for direct broadcast satellites. The C-MAC / packet message can be transmitted in the D-MAC / packet residual sideband amplitude modulation mode over the broadband cable channel (at least 10.5 MHz). The C-MAC / packet code can also be converted to D2-MAC / packet transmission over a narrow-band cable channel (at least 7 MHz), but with half the sound / data reduction, and due to the bandwidth limitations of the residual sidebands, Decomposition has also been reduced. Unlike the C-mode, the digital sound / data group in D- and D2-MAC / packet is not a binary but a binary binary code, which is then inserted into the baseband signal to jointly modulate the carrier. There is no difference between the three MAC / packets in terms of the video specifications themselves (MAC), but with D2, the potential for future scaling of image aspect ratios is limited by the inability to shorten the data string. The Federal Republic of Germany and the French government reached an agreement in June 1985 that they agreed to use D2-MAC / packet directly in live satellite TV-SATs and TDF-1 without going through the intermediate transition of PAL / SECAM. Therefore, D2-MAC / packet decoder must be provided by the end of 1986, this first batch of decoder can not fully comply with European Union technical standards, the minimum technical standards agreed with France, see the text of the appendix (not translated, See the original).