Originally Posted by BCF68
analog is SD though.
..but, not all SD is analog, thus the confusion when people discuss SD. If you say "analog", we all know it's SD. If you say SD, it may be analog or digital, since both still exist.
Originally Posted by domino92024
Sigh...Analog is NTSC. SD is a digital tv term.
His cable system has three types of video: analog NTSC, SD digital, and HD digital. Referring to both analog and digital signals as "SD" only causes confusion in threads like the OP started. When TV was all analog, nobody ever mentioned "SD." It was just NTSC analog.
eh, yeah....but....standard definition is still standard definition in an alaog form or a digital one. The difference is whether it's NTSC (analog) or ATSC (digital). SD vs HD refers only to resolution parameters, not the form of the signal. HD, given enough bandwith, can be sent in an analog form - it just needs a whole lot of frequency space, which is why digital was used. It fit into the same 6Mhz space as NTSC SD video.
We never spoke of SD before HD came along because there wasn't an option before. It's the same priciple that up until color TV came about, it was always just "TV". Once there was a difference, people referenced whether a program or their TV was color because, for a while, either was possible. Likewise, people almost always just say "TV" and it's usually assumed that, if available in HD, the reference is to HD, especially on an HD forum.
Analog Betacam is SD. Digital Betacam is SD. Some of those low power stations out there still using analog NTSC signals are SD, while those little subchannels stations are ATSC SD.
Granted, we usually only have to say analog to denote analog SD, because we never had an analog HD spec in this country. ATSC, on the other hand, ranges from SD all the way up to HD (and potentially beyond, if new compression schemes allow for greater efficiency in the 6Mhz system).