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General Asylum General audio topics that don't fit into specific categories. |
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In Reply to: RE: Here's A More Direct Source posted by Bromo33333 on December 12, 2016 at 14:56:33:
"the modulation for color TV was a very complicated one with AM, FM and all of that mixed up at once."
Not exactly, unless you are including the sound carrier.
The chroma signal is like the FM L-R channel in that it is carrier suppressed. Also, the detectors in an FM tuner for L-R are actually synchronous detectors. The detectors in the NTSC system had two synchronous detectors, one running 90 degrees out of phase thus yielding two discrete signals.
As with FM, it is not that different on the transmitting end. But it is a bit more complicated than that. The I signal had a bit more bandwidth but only a few TVs could use it. The RCA CTC111 I believe had what was called "wide I" demodulation but then they used a crap CRT. It was the early days of the inline gun CRTs and the picture would have been much better on a delta gun CRT. The pitch of those early inline gun jobs was so poor they shouldn't have bothered. Wide I demodulation also required another delay line. That chassis also had one of the earliest digital COMB filters on the market.
The I and Q signals were the difference signals for red and blue, I forget which is which. The green was derived from a matrix circuit, when the red and/or blue went down, it made the green go up and vice versa.
There is some complex math involved as they found that the green carried the most detail so it was fairly predominant in the monochrome signal, which underlies those difference signals.
But there was no FM in there, that was phase modulation and was not even intentional because when you mix two waveforms that are 90 degrees out of phase you get different phases which range from the instantaneous to the quadrature.
More useless knowledge, I have tons of it.
Getting back to the OP here, these ultra good digital formats will happen when not only the media is invented, but when the sources are available. I listen to some music from the 1950s and find a 128K MP3 to be quite adequate, though even on that material I have sometimes noticed a difference with a higher bitrate file. When I downloaded I would get several copies of everything and delete the inferior ones. It is actually somewhat surprising how good some of those old recordings are, considering the times. Others not so good.
There is now the holographic disk. It makes blu-ray obsolete. It has so much capacity nobody can use it. Perhaps that is the medium of choice. The ultra high quality formats would take downloading back to the 20th century, like it was on dialup. Imagine a five minute song being 800 MB.
Here's a wiki on those disks :
https://en.wikipedia.org/wiki/Holographic_Versatile_Disc
If you wanted to send someone a song, depending on your internet speed you might be better off just burning one of those and snail mailing it. However the technology has not been perfected. They've apparently done it but it is not quite market ready I guess. But they're talking capacities up in the terabytes.
They get that ready, THEN you can throw away the vinyl.
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- RE: Here's A More Direct Source - JURB 18:23:05 12/13/16 (0)
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