Stripping the magic from television, a brief electronic introduction. What are some tv similarities?
By David Warren
I believe it began with my grandfather’s Big Ben alarm clocks of which he had many, all of which I dismantled at one point or another. As far back as I can recall I dismantled anything I could get my hands on to see if I could recreate it as well as too see how it worked. Most of my tinkering was harmless but I do recall getting a well deserved beating for my experiment of removing a light bulb and dropping a speaker magnet into a live socket. That was the first short circuit I created.
Although I read volumes of material on how video and television worked it took a degree before I truly understood that there was no magic within. Thus the challenge; I’m going to see if I can effectively explain how television works in a single hub without boring you the reader to death.
Although my initial learning was based entirely on Cathode Ray Tube, CRT monitors, I will also touch on the differences between LED, LCD, and Plasma monitors’. First things first though. The pantelegraph was the first device capable of electronically reproducing an image. Ironically the most relevant component of this invention was timing, perfectly synchronized clocks in different locations. The sender wrote a message or drew a picture on tin using non-conductive ink. This could then be scanned and sent via a telegraph wire to the receiving station. The receiving station would use paper soaked in potassium ferrocyanide. By having two perfectly synchronized clocks controlling the movement of two identical machines simultaneously the stylus of the receiving machine would electrify the soaked paper producing an exact image in Blue Prussian ink. Giovanni Caselli developed this technology in France in 1862. Although this constitutes the invention of the facsimile it was in fact the first way to reproduce an image electronically. Mainly this device was used by banks to verify signatures.
Fast forward to America 1907. Lee De Forest invented the vacuum tube (Audion) which could take very small electrical signals and amplify them. Devry University was originally the Lee De Forest Training institute. Thanks to Thomas Edison among others the motion picture business was also rapidly expanding at the same time.
1927 Philo Farnsworth, a farm boy in Utah invents television! So now we have a working device that transmits moving images electronically!
How does it work? This is the hard part. You have a camera that takes each still frame and breaks the picture of that frame down into the smallest pieces that a receiver can reproduce, called pixels. Then we send this information using AM (amplitude modulation) to a receiver. The receiver must first be tuned in to the frequency (carrier) and then amplified. Now the signal must be demodulated from the carrier and sent to the monitor in a way that will recreate the original image. The timing is what is crucial here. Both horizontal and vertical synchronization must be on the money in order for the electronic beam or beams to provide a correct raster which is what produces the image on the receiver. The audio is sent using FM (frequency modulation).
HDTV and scanning. The method of scanning on most all monitors currently sold is (P) for progressive scanning. When you see a monitor rated at 1080i that would be referring to interlace scanning. At lower resolution such as 480i compared to 480P you would see a huge difference in that the progressive scan would be much better. There are those who would argue at the 1080i versus 1080p level you could not detect the difference. As all HDTV monitors are manufactured with progressive scanning currently this issue is a moot point.
Plasma, LED, or LCD? If you have an elaborate high definition collection of art that you enjoy presenting on a 60” plus screen you probably want a commercial grade plasma monitor that will set you back give or take $8,000. Yes, the individual pixels change colors faster and black is true black although your expensive monitor will use a lot more energy and produce a lot more heat as well as give you burn in if you leave the same video on it. For the rest of us an LED or LCD monitor will more than suffice for ten times less the price. As the electronics and processors have become so fast and advanced I am content without upgrading from my LCD to a newer LED. This may sound bold but I am willing to bet that if I can’t tell the difference in picture quality neither will you.
That was a lot of information for a person such as me, who despises television, to convey. I do however love movies and want the best audio and video quality I can afford.
Comments
Hi Katharella!
Enjoyed your comment, lol, Paris was nice. I missed a few days here as I was installing the (ROFL) "last" desktop I'll need, that I replace every five to seven years. After a few weeks of deliberation I went with an ASUS. New i7 2600 processor was the selling point for me, still felt the need to swap a few things such as the slow SATA hard drive and graphics card but I'm happy with it. The last three were HPs' but I think they are relying on their previous reputation too heavily. Like the ASUS thus far. Gave my daughter my HP and a 27" Westinghouse monitor. I went with two 20" monitors in place of the single, working out well.
I enjoyed "The Net". Likewise should anyone want my current identity, their welcome to have it, bills,bills, and more bills! Updated the computer with money from the company that built my "exploding" aquarium heater.
David,
Great Hub!
Thanks for a very interesting and informative read. It really puts into perspective the foundation that was established which has lead to the consumer electronics we enjoy today!
It’s a wonderful trip down history lane to remember the creative, diligent and patient work of those who pioneered the multi media and communication industries.
It brings back memories of my dad and I building an old black and white vacuum tube television with a RCA correspondence course. I’ll be sure to share with him as well :-)
Silly me thinking you could be a FEW steps ahead of times! Well, yeah believe it or not lol, in my quest for "how things WORK" I took a class and learned how and WHY the 286 was so slow. After I took DOS classes I was like "if they discombobulated the molecularobstacle and installed innards with a T-3, it could go a wee bit faster" they look at me if I was crazy LOL! hehehe... I did take the classes, my dad got my son a computer and we went price checking and the lady said "YOU'LL NEVER NEED MORE MEMORY THAN THIS" and I said "but I need WordPerfect for school" Well, Wordperfect won't fit onto the hard drive" .. Um, then WHY was it I'll never need more memory for $2,300.??? LOL She walked away. So did we. My teacher laughed too. She said one day, these will make you laugh.. I guess that day is here! Further into college when that movie "the Net" with Sandra Bullock was out, and her identity was stolen.. I said to my professor (you can tell I always had a comeback)LOL "That can't happen, someone knew her, a teacher, a doctor, a friend, SOMEONE, she wasn't always a loner".. Finally she said "Miss Kathy, don't ever think anything cannot be possible." Before I could get the next "but.. but. hey..." in, she moved on! LOL now.. it's possible, but at the same time funny because if someone stole mine, BOY would the joke be on them! hehe.. "thanks now you can pay off all my maxed out credit cards" LOL! Hope ya had a great night in Paris! (I'm actually in Beijing in a game :;sigh:: still fun tho) LOL! Not a fan of China, but it's like shopping with fake money and fake clothes I'll never get to keep LOL! (and No worries of eating a cat or getting back home)::whew:: lol
Hi Katharella! We get a few shakes now and then, I live on the eastern side of the Sierra Nevada. On the Truckee River in Reno. I LOVE 'google earth'. Used to take hours back in the dial up days, now its truly amazing. Who knows, maybe in another decade we'll all have T1 lines. When I was in college I remember how excited I was when we went from 286s' too 386s' thinking we were "all that" because we could debug in DOS. So, off to Paris now. Thank you for commenting and have a great evening!
LOL.. you men, all of ya have to take things apart it seems! I guess like I said mine started out with my dad, so that's fair LOL! My bf is also a taker-aparter LOL
I have a friend who is almost done with her schooling of Archeology and Geology and I don't know where you live (sorry I didn't look lol) but we live on the west coast and according to all their studies we live in the safest place on the planet aside from hurricanes LOL! So hopefully you're not in California because that's right over a fault line! Oh, you should download Google earth if you haven't already, it shows where the ocean floor is deepest and shipwrecks and all kinds of info! It's a great program and free from google! Just do a search on there for "google earth" and it's just AMAZING.. type in your address and see your house! You can delete it out if you don't want it in there though. But if the google truck goes by, they'll put it back in! They took my houses picture when my lawn looked horrible! LOL! I'm going to take it down when I get another hub built! I want my 100 back! :) Hey you can take apart the WHOLE WORLD and not even get in trouble LOL!!! And tell you wife, you're taking her to Paris! :) It let's you click little places to see everything almost close up! so you can have a nice little dinner anywhere you choose, uninterrupted! :)
Hi Nelleanna, for a moment I thought uh oh, better not let my wife see that comment. She just said that your comment was very nice, and to me, "Who are you kidding, I know you'll never change". Sooner or later I just have to see the inside of everything,lol. I'm glad you enjoyed the hub! Some of the things that interest me technically really do bore many others. Very happy to have you as a fan!
My beloved George was an Engineer and an intrepid taker-aparter of things, and became almost a menace in his latter years! :-) I had to post notes on my computer and the coffee pot to the effect: "Do Not Disassemble!" It still required a watchful eye!
I loved this hub, David. It's a fascinating process and not one bit boring. Thank you.
Your right, absolutely amazing. I've always had the feeling that some catastrophic event may change all of what we enjoy. I just hope it is not in our lifetimes,lol.
Isn't it amazing in just the past 60 years how far technology has come, when you think about how long people have worked at communication? Actually kinda spooky! Like why did it take so long, then excel so fast!
Thank you! That is awesome Will. I ran my own business for awhile back east doing consumer repair. You brought some amusing memories back about having televisions, receivers, and VCRs' all over the house. As you can imagine my wife was just thrilled, many years ago now.
This brings back great memories. I grew up in the glory days of radio and the beginnings of television, and I was fascinated. I built my first crystal radio as a cub scout and a one tube radio soon after. Both worked! I learned to read schematics and also learned about the various circuits. When I was 13, I got a job repairing radios and later, TV’s. My teenage room was filled with what are now antique radios and TV’s that were abandoned at the repair shop.
Great Hub!
Thank you both!
lady shanaya, yes,lol seems curious and mischievous often share paths!
Hi Bret, yes that was interesting to me as well. Seems in most cases an inventor's invention rarely is used for the purpose the inventer originally had in mind. Giovanni's focus was on sending pictures but the only real money made on the patent was for banking signature verifications.
Hello David, another great hub. Your flexibility of writing style amazes me. Always good and always interesting with personal touches.
I was fascinated to see the part about the pantelegraph, amazing to think that the fax machine actually came before the telephone.
I was glued to your above HUB..very Informative & Helpful.Thanks for sharing this GREAT HUB sir DAVID.
PS: Being a female i was very scared of Flame & Short circuits in my childhood days. But You were MISCHIEVOUS it seems.
David Warren 12 months ago
Hi StayPos!
Thank you for such positive feedback! I am absolutely amazed by the speed we race forward regarding multi media and communications.
I used to use my dads' HAM radio that was tube technology as was as my first oscilloscope. :)