Visual "clipping"?

Hi:

Clipping in an audio signal results when an audio device receives a signal that is too loud. The audio signal distorts into square-waves because the "tops" of the signal are flattened. The device cannot handle power levels over a certain level. When this level is exceeded, clipping occurs. Clipping is usually harsher in digital devices than in analog devices. Analog clipping tends to be fuzzy and soft compared to digital clipping.

What is the visual-equivalent of "clipping"? Is there a difference between analog and digital in terms of visual-clipping? If so, what is the difference?

Auditory-clipping can damage speakers. Can visual-"clipping" damage monitors?

Thanks,

Radium

Reply to
Radium
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Clipping causes whites lose all texture -- very similar to overexposed film.

No. Prolonged blacks can damage television transmitters, however (video is inverted for transmission, so black requires full power from the transmitter).

Isaac

Reply to
isw

What does this look like on a screen?

Prolonged black can damage a monitor/screen? That's weird. White is analogous to the loudest sound a loudspeaker can playback. Black is analogous to a loudspeaker not being feed any signal.

When the power-supply of the monitor/screen is turned off, the monitor/ screen is black because it not receiving any voltage.

I would think that extremely-bright white would damage the screen because the brightest white results from the highest voltage applied to the Reds, Greens, and Blues [equal intensities of R, G, & B -- if combined -- appear white to our eyes when emitted by an electronic monitor] in a particular area of the monitor/screen. If the voltage exceeds this for prolonged periods of time, that region of the screen will burn out, much like forcing an extremely-high voltage audio signal into a speaker will cause the speaker to short-circuit and the diaphragm to pop and/or melt. Many instructions manual for speakers give direction not to reach or go above the clipping point and clipping damages the speakers. Wouldn't something similar happen to a monitor/screen [whether it's a CRT, plasma, or LCD] if it was forced to display light-intensities beyond its limits?

Reply to
Radium

snip

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More Trolling.

Exactly where did he say prolonged black can damage a monitor/screen

Reply to
Don Bowey

But is it trolling or is Radium just inattentive to details because he's too excited about the conversation?

--
Al in St. Lou
Reply to
Al in Dallas

Al, the uninformed just don't get our humor, even if we try to explain it to them. I was an engineer at an AFRTS TV station at Ft Greely in the '70s. I had a problem with a couple of the talking heads on our live newscast. They wouldn't stay in their seats, or even on set during actualities, so I rewired their off air monitor. The next newscast they got up and were shadow boxing in front of the news desk when the sound went dead, and they thought that they were on air, in their dress uniform jackets, and underwear. (No air conditioning at the station). Needless to say, they freaked out! The next time they got out of line was a Saturday noon newscast, where a fishing program from a station in Fairbanks was on their off air monitors. :)

My best pranks at the station? One of the staff was a drunk and he was always bragging that he was too smart to get caught. The late night DJ had relatives that worked at a NOAA weather station nearby, and a lot of nights they would bring him supper. They had brought the bottle with the food, and it might have had a quarter of a cup. I was going to make a bank out of the bottle, but I couldn't carry it back to the barracks that night, so I hid the empty wine bottle inside the console, behind a rack mount CCU power supply. The station manager found it, and raised bloody hell. The guy drank so much that he truly couldn't remember if it was his bottle, so I just stood back and enjoyed the floor show. before it was over, he admitted to drinking on duty, and apologized for leaving the empty bottle. The manager pulled him from engineering rotation, then put him on day shift in the film library.

Another time we had a general from the Pentagon visiting the base. He called the station and didn't identify himself. He ordered me to run something else, because he had seen the movie the week before, in DC. I replied, Sorry sir, but I haven't seen it, and hung up. He called right back, and started yelling that he was a general, and that if I didn't obey his order, he was calling my commanding general. I laughed and said, "Tell him that Michael said 'Hello'." He snarled "What the hell does that mean?" I laughed and told him, "My General will explain it to you, if you're stupid enough to call him". He proceeded to brag about all his friends in DC, so I reminded him that he wasn't in DC, but at the US Army cold weather test site, 105 miles from the nearest real town. Then I told him all the places that I had friends. He grumbled, "One damn phone call and I'm out of here!" I asked him how he would find a working outside phone line, or mail a letter if word spread that he was trying to disrupt our only entertainment. Then I twisted the knife a little more and said, In fact, if you piss off the wrong people, they will lose your orders, and report you as AWOL and last seen heading for the Bering Straits, and Russia. Your Pentagon friends wouldn't help you if they think you're a commie, will they? He never called back. Was it something I said? ;-)

My all time favorite was running a station ID in color, on a B&W only '60 RCA and Gates plant. The Base Information Officer was telling everyone that the station could not be converted to color. I don't know about you, but I have never let the 'unwashed' tell me what I CAN'T do. I borrowed a Heathkit color bar generator, made a custom 35 mm ID slide with parts from the slide repair kit, and dry transfer lettering from the leftover bin in the newspaper office. I used the very basic video keyer in the '60 vintage RCA video switcher to invert the video from the film chain to display: AFRTS CH8

in bold colors on a black background. Boy, did the excrement hit the rotary oscillator! The shit hit the fan, too! ;-)

Five seconds later, the control room's private phone line was ringing. The base information officer was screaming, "Soldier, you've just made a fool of me!" I replied, "But Sir!, You've always bragged of being a self made man!". He never spoke to me again, or bothered anything in the radio or TV station. I know he called my commanding general, and was told to leave me alone, and stay out of the transmitter and control room, for his own good. :)

I had an ongoing problem with the base power plant. They intentionally caused brownouts, and used us as a power dump. I was less than five minutes into the first of three reels of kinescope of the '74 world series when my line voltage dropped from 120 VAC to 25 VAC, shot up over 210 VAC (the upper limit of the AC line meter), and was tripping circuit breakers all over the complex. That was the final straw! After I picked up all the pieces of shredded film, I had one of the DJs cut a custom 30 second cart with "AFRTS CH8 will return to the air as soon as the AC power problems are resolved. If you have any questions call: XXX-XXXX" The phone number was an unlisted line into the power plat manager's office. He got several *hundred* phone calls, and I never saw the line voltage vary more than 5 volts after that. ;-)

In spite of all this, I had turned a station that could barely sign on each day, into one that ran over seven months without an on air failure. I made E4 at around 20 months and received a letter of commendation from my commanding General.

A few weeks after I left that station, the two chief engineers from the Fairbanks TV stations paid a visit to "Help out the poor dumb GIs at that crappy little military TV station" They were pissed off at how well the station was running, and admitted to the other engineer that it was in better shape that either of their stations. My friend Neeley "The Hoop" asked them, "Do you remember the soldier that you refused to give the nickel tour of your stations"? He did all the work.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
Reply to
Michael A. Terrell

Now THAT is CLASSIC! :)

Reply to
Matt Ion

Its too bad that I STILL can't tell the really good stories. :(

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
Reply to
Michael A. Terrell

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