Dorothy on old RCA 'CED' disc

[Ed in Tx]

Originally Posted by lnx64

Makes a little more sense. So it's basically describing how defined the horizontal line is. So for example, like 240x480 for example would be 240 lines, right?

Well sort-of. If you are talking picture elements yes. How many elements each horizontal line can be divvied up. But that 240X480 could be misconstrued as aspect ratio.

[Eric H]

I was working in an Electronics Store when these came out and I remember the first day.
The player was hooked up, TV turned on and Play pressed, pretty much everyone was underwhelmed by the picture, not that it was bad but the owner of the store was big into Laserdiscs and the CED suffered badly by comparison.

The skipping was an issue from day one as mentioned, also there were artifacts in the picture, little sniglets here and there on the screen, not really bad but still disappointing for a format that had such a big build up. It was like "We have VHS why do we need this?"

They are pretty cool in that they are basically a mechanical means of reproducing video!

I have a couple of the discs on display in my living room, mostly because the artwork on the big cartridges looks really nice.

[oldtvman]

We were an authorized service center and worked on tons of the ced players. If they had introduced it ten years earlier they may have sold more. The stylus were good money makers.

[AiboPet]

To me...this is astonishing!

A color stereo picture, from a stylus! I guess this must have failed long before it reached Hong Kong....or I was just not paying attention. I've never ever heard of this, and I was an avid LaserDisc fan. I still have my Panasonic player that plays both sides of a Laserdisc...and a few of the discs.

I should some day get that player back on a shelf where I can regularly play it. It worked about a year ago when I last played a Japanese concert (Yellow Magic Orchestra's "Propaganda").

Can't wait till I see one of these CEDs playing someday....no matter how "underwhelming" it looks.

[ceebee23]

I have both an NTSC and a PAL player (yes they did release a PAL version) .... and a range of disks. The quality is slightly better than VHS with similar resolution but a better signal to noise ratio.

Interestingly RCA found that they sold fewer players than expected but vastly more disks than forecast.

Ironically playing the disks reduces the skipping ..so a new disk may skip but after a few plays the skipping is far less. A good stylus is a definite requirement.

CED was one of those things that I never expected to obtain. The PAL version was only released in the UK. But one day at a party a friend casually mentioned he had seen a weird disk video player in a local electronics store, literally a mile away from me.

This was in the late 1990s.

I rushed around the corner to this shop the next day. The owner had imported a few Hitachi players in the early 80s. So there was my holy grail .. brand new, in its box just waiting for me!!

(In the end I bought his two remaining players and shipped one to Tom at CED Magic in exchange for a US player).

The two players still work beautifully and I sourced stylii on eBay. (A very helpful man in Florida supplied me with them!!)

Blu Ray they aren't but still a pretty amazing technical achievement.

[old_tv_nut]

The CED format changed the color subcarrier to a lower frequency for better readout, but still mixed with the luminance. It required a comb filter in the player to remove the resulting very coarse dot pattern that otherwise would be visible. The result is that the output had reasonable horizontal resolution but poor diagonal resolution. RCA had some demo material of a car going over a suspension bridge, and you could see the vertical wires, but the diagonal wires tended to disappear.

The sensing of the disc capacitance depending on detuning a resonant circuit that carried a 915 Mhz oscillator signal. This was the same frequency as early microwave ovens, which could interfere with the CED player.

[NewVista]

Seems all CED discs have good A-list movies on them, the Studios were clamoring to resell films on this format!
The execs at RCA & Hollywood blissfully unaware of the extreme mechanical challenges and reliability issues to soon surface.

[Penthode]

Originally Posted by NewVista

Yes, depends on TV, some H stability shake, needs slower time constant ?

I had never thought about this before. So the spinning video disc has the same sort of timebase errors as video tape when no timebase correction is used?

Bending or jitter requires a "faster" or reduced time constant. Uncorrected timebase errors from VHS tape needs the reduced time constant horizontal AFC low pass filter so that the horizontal oscillator keeps step with the velocity errors.

I found it interesting to find that negative modulation for North American 525 line TV broadcast required a horizontal AFC circuit to help overcome false triggering with noise impulses whereas older British televisions receiving positive modulation 405 line transmissions did not. I suspect this was because the horizontal sync pulse was at the modulation envelope peak for 525 which made it more susceptible to noise? I recall weak British 405 reception on sets with horizontal AFC locked well under the noise.

[old_tv_nut]

Originally Posted by Penthode

I found it interesting to find that negative modulation for North American 525 line TV broadcast required a horizontal AFC circuit to help overcome false triggering with noise impulses whereas older British televisions receiving positive modulation 405 line transmissions did not. I suspect this was because the horizontal sync pulse was at the modulation envelope peak for 525 which made it more susceptible to noise? I recall weak British 405 reception on sets with horizontal AFC locked well under the noise.

Exactly correct - with an envelope detector, impulse noise goes toward max signal. With negative modulation, that means it goes into the sync region. Better NTSC set designs included a noise inverter so that impulses going beyond normal sync level would be inverted and go back toward lower signal level (away from sync, towards white). The time constants in the inverter would be much shorter than those in the sync circuit input filter, so the narrow noise pulse that remained would not affect the sync separator.

[old_tv_nut]

Originally Posted by Penthode

So the spinning video disc has the same sort of timebase errors as video tape when no timebase correction is used?

The disc output is continuous through vertical sync and therefore does not have the sudden offset of H sync timing that is possible with tape - no "flag waving" at the top of the image even with slow AFC, but the smaller random timing variations will be visible.

[wa2ise]

Originally Posted by old_tv_nut

The disc output is continuous through vertical sync

There was a crude attempt to reduce the time base errors in the CED players. There was a feedback mechanism that moved the pickup stylus perpendicular to the direction to the disc's center. They used what was essentially a speaker voice coil as the driver of this stylus mover. This was to counteract errors due to poor disc centering and turntable wow and flutter. But feedback loops reduce but not completely remove such errors, if they tried they could overshoot and go unstable.

Early CED players used a synchronous AC motor fed by the 60Hz powerline, so the disc would rotate at a speed to produce vertical sync at 60Hz. The color subcarrier was recorded on the disc at around 1.53MHz, and the player would upconvert that to the 3.58MHz NTSC standard, using a beat oscillator around 5.11MHz. The above time base errors would also show up as subcarrier frequency errors, so the beat oscillator frequency was FMed to counteract that, to produce a stable NTSC 3.58Mhz subcarrier.

Back in the day, TV sets' horizontal was designed to cope with erratic horizontal sync from VCRs.

DVD players use digital FIFO buffers and frame store memories, and they control the disc spin rate to keep these buffers and memories half full, and thus produce precisely timed video.

[bgadow]

I have a couple RCA players and need to get one of them working properly one of these days. Both have belt issues; I think I replaced 1 or 2 belts in the one but then figured out the that main drive belt needed replacement as well. One issue I remember is I couldn't get them to play all the way to the end of a side. A few years ago I used a CED player in conjunction with an old TV(10BP4 era) to do a demonstration somewhere. The machine kept acting up but one thing that came out of it was a guy saw it and asked if I wanted some discs. A few months later he showed up in my driveway with a stack around 4' tall! I could be talked out of the players and the whole stack without much trouble.

The one TV shop I cleaned out was an RCA dealer; I was almost done after many months when I found 3 CED players tucked away. One was truly NOS, never opened; the second was his demonstrator. The third was a lemon that he was never able to get working right. I let them all go on ebay. He said for a while he did a brisk business in disc rentals but it dried up pretty quick.

[ChrisW6ATV]

Originally Posted by old_tv_nut

It makes me shake my head, but when you look at formats that succeeded and those that didn't, there is a correlation to whether porn was available or not.

That didn't help the HD DVD format, though. Early on, Sony (that controlled the Blu-ray format) said it would not release porn video on Blu-ray, but porn HD DVDs were available pretty quickly after the debut of both formats.

[ChrisW6ATV]

Originally Posted by lnx64

I have LaserDisc and the only thing I had ran into was anime porn. Yea, not real stuff, just animated. lol

There were definitely numerous "real" porn Laser Discs available. Image Entertainment, now one of the major home-video distributors, got its start by releasing porn discs. At the time, most Laser Discs were made in Japan, which has laws regarding porn if I remember right (and see my comments about Sony, above), but Image contracted with an American manufacturer (perhaps the only one at the time) to make its discs.

Now, I hope people don't get the wrong idea when I seem to know a lot about porn on video disc formats.

[Sandy G]

My 1st CED disc was "Dr Strangelove", I think I got it as the "Free" one I got w/the machine. The local dealer DID have quite a good selection of movies, but the "popular" ones all suffered from the annoying "Skip" problem. Actually, the "Soft" focus really WASN'T a problem, it sorta made up for the "Artifacts" that typically showed up on a VHS movie of the time.