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Fifty Years of Color Television
peter303 writes "The Houston Chronicle notes that color TVs were first manufactured on March 25, 1954 at a price of $1000 (about $4000 in today's dollars). Some of the older folk here remember the excitement of your first neighbors acquiring one of these in the 1960s and as the TV series one-by-one switched to color. Ironically, for such a high tech nation, there hasn't been a major quality improvement in TV broadcast images for a half-century until the 2006 changeover to HDTV."
Yea, but when will slashdot get some new colours too?
...and there's STILL nothing on!
1669 hours... a perspective:
If you are awake 16 hours per day 1669 hours is 104 days, not "just" 70. Apparently, on average, adults watch TV 29% of their waking hours. If you work/commute 45 hours per week, your "free time" is, if you do nothing else, about 9 1/2 hours per day, of which, on average, you watch TV 4 1/2 hours.
So the average adult uses more than half of their available time watching TV.
Pretty sad.
Amy
Actually, there have been numerous quality improvements, though they have come in the receivers, rather than in the NTSC standard. The standard itself is rather elegant, and apart from the error that resulted in shifting to a non-integer frame rate (and the problems that has created for designers of hardware for decades), it has proved very robust.
--- Bill
Cheeky buggers.
I remember when business desktop computers first went to color. First the IBM PC and then the Mac (technically I suppose the Apple ][ was a business machine). "Ah," I thought to myself, "this will never catch on..."
Ironically, for such a high tech nation, there hasn't been a major quality improvement in TV broadcast images for a half-century until the 2006 changeover to HDTV.
Was HDTV really even necessary? Our tax dollars were spent mandating its deployment, our money will be wasted purchasing the receivers (which are going to have to be in all TVs), and what does it do for us? Nothing.
We worry about the effects of lack of exercise, overeating, diabetes, etc, yet we mandate better TV signals and are double paying for it.
My dad recalls (born in 1952) when his neighbors got color TV and he remembers everyone on the street tried to get in the house to watch it.
He remembers one time when it broke and the whole neighborhood pitched in to fix it...
Last time I was in Britain, I made some comment to a cousin of mine about their wide-format TV and all the shows that are shown in that format. She responded "Yeah, we just go that last year, we're so far behind North America". Boy was she surprised to hear that we're still years away from that change over here!
And of course the fact that PAL is higher resolution that NTSC, and we realize how little has changed in this past 50 years. Why exactly has it taken North America so long to change to a better format? I'd imagine the HDTV change will happen almost overnight, much like the DVD revolution, but it sure took a while for the quality of TV to step up a notch.
Now if they could only do something about what's actually ON the tube.... or, um.. the flat panel?
actually, the quality hasn't changed, back even further than that. since color tv was to be able to be forwards and backwards compatible with black and white, the color signal was hacked into the black and white standard.
this was not the case in britain, where a new, but incompatible, standard was created, that used bandwidth more effectively, and had better color.
so hdtv is the first new standard since about 1939. it's about damn time.
this proves, once again, that standards are a double-edged sword. use and choose carefully...
stored on computers from birth to the grave
I don't know about the TV image qualities where you are, but Cable TV certainly improved image qualities. Ok, ok, this is not an improvement on image quality, but on transmission, but to the people sitting at home, it didn't make a difference. Why do I bring it up? Because Cable TV allowed for additional channels and offered image quality good enough that people are willing to pay to subscribe to it. And quite frankly, no matter how good the pictures, if you don't have good transmission/reception, it's still pretty crappy.
I find no confort in being able to watch "My Big Fat Obnoxious Fiance" in HDTV...
The perfect sig is a lot like silence, only louder
But what about digital TV broadcasts, we've had these for a few years, and they've certainly made a big difference to the old analogue signal. Plus there's also audio improvements including Mono -> Nicam Stereo, and Doly Digital 5.1 broadcasts through digital satellite transmissions (using Sky+ for example). AND we also have receiver improvements, including CVBS -> S/Video -> RGB -> Component, and 100Hz TVs, widescreen TVs...
To say that there have been no major quality improvements in color television isn't entirely correct. The televisions themselves have implemented better and better filtering algorithms and can better lock onto signals than they used to. Color realism has gotten better with newer TV's to project more fleshy tones and more accurate color temperatures.
Then there have been improvements in the means of broadcasting signals. Cable TV was introduced, and not too long after was followed by satellite reception (with their appropriate receivers), both of which improved the strength of the signal and integrity of the image. In more recent years, digital cable and satellite hit it big, and allow for near-perfect signal quality and picture integrity.
The only thing that hasn't really changed up to this point has been the resolution, and this has partly been a result of how well the TV market took off after its introduction. It's hard to change a standard once it has been in place and is used by everyone. Optimally, it would be nice if there was a way to allow HDTV signals to continue to be received by regular definition TVs so that broadcasters wouldn't have to maintain separate equipment, but the technology is so much different that it would be impractical. This is why the introduction of HDTV has taken so long.
KappaStone
Can you provide a link to this "non-integer frame rate" please?
e ld_NTSC _sequence/index.html
Look here:
http://www.poynton.com/notes/video/Four-fi
--- Bill
Area Man
-- taking over the world, we are.
In theory, the quality should have been OK, and perhaps it was in a studio, on a high-quality monitor, via closed circuit.
In practice, the home receivers of the late 1950s and 1960s were lousy. They were very temperamental beasts. They had no built-in degaussers and if you moved them or turned them you'd get color changes due to the earth's magnetic field.
The tube circuits were unstable and drifted. They had no ability to compensate for any signal variation, so colors shifted from program to commercial, from program to station break, from program to program, and sometimes from camera to camera within a program. You were constantly leaping up to fiddle with the contrast, brightness, saturation, and hue adjustments.
The tubes were never properly converged (and had about seventeen tweaks needed to converge them).
The picture tubes were circular rather than rectangular and cut off significant parts of the picture. The phosphors couldn't deliver much brightness, so they couldn't put the usual neutral tint in the CRT face; a set when turned off looked pale grey rather than dark. When turned on, room light washed out the colors (and if you turned the brightness up the picture looked even worse).
They were trophies and icons of conspicuous consumption, but it wasn't much fun watching them. I've often suspect that at least part of the reason for the popularity of the Disney show is that animated cartoons were relatively unharmed by slight color distortions.
In the 1970s, solid-state circuits and the introduction of various AGC and other automatic-adjustment features finally brought home receivers to the point where they were worth watching.
"How to Do Nothing," kids activities, back in print!
No improvements??!! Don't you remember "vert. hold" and having to adjust that up until sometime in the 80's. IC-based PLL circuitry has really improved TV since the transistor and tube days.
Actually, the problem is that the frame rate is not an exact integer multiple of the 60Hz AC power frequency, which is usually the largest source of electrical noise. It's off by a fraction of a percent; that's why you often see a distortion slowly creeping up the screen about once per minute as the frame rate beats against the power line sine wave. If the frame rate were exactly locked to the power line frequency, the distortion wouldn't move, so you wouldn't notice it.
Uhhh... Okay. Credentials: Former professional video technician (at the SkyDome in Toronto) before being hired to design radar video systems for Litton. Also an avid collector and restorer of early television sets.
In the 1950s, AC power was not universal, especially in rural areas (note the sustained popularity of the "All American Five" AC/DC table radio at that time). Lots of places had DC, and lots of cities had 25Hz power well into the late 1950s. Nor was it necessarily going to be in sync from one town to the next, so you couldn't guarantee that the 60Hz powerline hum could be synchronized with the TV station's 60Hz vertical signal. In other words, you couldn't be guaranteed that the hum was going to happen in the vertical blanking interval (that black bar you see rolling when the vertical hold control is set wrong).
I suspect that the vertical was chosen to be at 60Hz more because the large current draw of the vertical output tube driving the deflection yoke would then be more likely to occur during the charge cycle of the set's filter capacitors, allowing smaller capacitors to be used (cheaper). This of course being a time when electrolytic filter capacitors (in fact, all small parts) were still hand made.
Even more importantly, you should remember that most early TV sets (until the advent of selenium rectifiers in about 1955) had full-wave rectifiers, generally using a 5U4 or similar tube. A full-wave rectifier folds the negative half of the sinewave up to the positive side, which effectively doubles the frequency to 120Hz.
Either way, if the set is operating correctly, regardless of color standard, you will not see any powerline artifacts or ripple. It's when the horizontal system starts to come out of resonance that the biggest current draw happens in the set. Your horizontal output tube (transistor) consumes the most power of any part of the set; if a typical 1950s DuMont or Admiral has a cathode current of 120mA (at ~300V) and you misadjust the horizontal hold, that current will spike to over double that. That will load down the set's power supply, discharge the filter capacitors more, and you might start to hear 120Hz (full wave rectifier at 60Hz) hum in the set's speaker.
IIRC, the original B&W broadcast was at 60 frames/second, but there was some technical reason they had to slightly shift it in order to add the color subcarrier.
Yup. The original NTSC standard was 30FPS; when the 3.58MHz sinewave which carries color was added, the bandwidth of the signal had to be increased. (The original was 3.5MHz bandwidth for the image; reducing the frame rate slightly was sufficient to keep the bandwidth inside the original spectrum and didn't screw up many of the existing TV sets.)
Old B&W TVs were the worst with this noise distortion because they weren't designed to try to prevent it.
Note that the NTSC color TV standard was adopted in 1953, though not implemented until 50 years ago today. Every TV set built since then has known about the new frame rate the sets would have to handle. I actively collect and restore early TV sets, and I only have a few which predate this - they're rate.
Again, you don't get powerline beat in the picture unless something is wrong with the set's filter capacitors.
If you're getting a beat in the picture which, on a blank raster, moves in time with the vertical hold control, then you've got a problem where the vertical is either consuming too much current, or a
Fire and Meat. Yummy.