Given that the video is passing continuously through the image keyer, my guess is that it may or may not have burst going in, but it does continuously coming out. It would be more correct to have the burst come and go with the boxes, both because that was the intent of the original FCC rules and because you no longer would have to examine the entire frame for chroma. A good thing to verify, but my guess is that we're not going to get our way on this one.

ak

 

I asked about the burst when there are no boxes.

It's unlikely the burst will not be present when the boxes are not there, but not impossible. It's worth the time to scope it.

 

Nothing has changed, The French today take English technical terms and sent it to some hallowed old man to be converted to a French word that's three times as long.
http://www.frenchtoday.com/blog/learn-some-french-computer-terms

Well, then it seems there should also be a little old man that removes the French words from the English Language and replaces them with English substitutes.
Here's a list to start.
Or is that too gauche?

 

Well, then it seems there should also be a little old man that removes the French words from the English Language and replaces them with English substitutes.
Here's a list to start.
Or is that too gauche?

I love the French but I was at this meeting with the chief scientist of a company's product we were having problems with. He spoke perfect English but had to translate French to his field engineer about how to fix it. They would talk for 5 minutes in French with waving hands and go on and on with every simple question until we would say, 'time out' what's the answer? The principle engineer was a Brit who knew a little French so after they had left we asked what took so long for the answers. They were arguing about what was the proper French word for him (Monsieur chief scientist) to translate to English about the questions not the subject of the questions.

 

Trigger a monostable on the line pulses. From this mono, trigger a second one to strobe out most (all?) of an active line period. Pass the video through a 3.58 tuned circuit, so anything that is left is colour within the active line. Amplify it and then use a detector to produce a DC proportional to the amplitude of the colour. use the DC to modulate/FM/trigger an audio oscillator.
Frank

 

Trigger a monostable on the line pulses. From this mono, trigger a second one to strobe out most (all?) of an active line period. Pass the video through a 3.58 tuned circuit, so anything that is left is colour within the active line. Amplify it and then use a detector to produce a DC proportional to the amplitude of the colour. use the DC to modulate/FM/trigger an audio oscillator.

Posts 31, 36, 41.

ak

 

Trigger a monostable on the line pulses. From this mono, trigger a second one to strobe out most (all?) of an active line period. Pass the video through a 3.58 tuned circuit, so anything that is left is colour within the active line. Amplify it and then use a detector to produce a DC proportional to the amplitude of the colour. use the DC to modulate/FM/trigger an audio oscillator.
Frank

I vaguely remember having seen a critically damped crystal controlled colour subcarrier oscillator.

The colour burst would kick the oscillator into action, the decay was adjusted so the oscillator just about kept going until the arrival of the next burst.

I think it was the "colour killer" circuit that gated off the chrominance signal if properly locked decoding couldn't be assured.

 

You remember correctly. Some low cost TVs limped by with a high-Q tank that rang for an entire line (63 us).
"color killer" - haven't heard that in a while. High school was a looooooong time ago.

ak

 

Israel was for a time the "color killer"

Color eraser (mekhikon)[edit] It has been suggested that this section be split into a new article titled Mekhikon. (Discuss) Proposed since July 2013. In the '70s, the Israeli government considered the import of color televisions as frivolous and a luxury that would increase social gaps. Therefore, the government ordered the Israel Broadcasting Authority to erase the color from color-taped telecasts by erasing the "burst phase" signal. The "damaged" signal triggered the "color killer" mechanism, installed in color TV sets to prevent the appearance of color. This method was named mekhikon (Hebrew: מחיקון‎ "eraser").
....
Color anti-eraser (anti-mekhikon)[edit] Soon after its introduction of the "Color eraser", special TV sets with an anti-mekhikon (Hebrew: ×× ×˜×™-מחיקון‎ "anti-eraser") device were offered. This device re-constructed the burst phase signal according to several known standards. The client had to turn a switch until the pictures on the screen appeared in natural colors. According to a report in Yediot Aharonoth from January 1979[4] clients had to manipulate the switch every 15 minutes on average in normal conditions, or up to 10 times an hour when special problems occurred, in order to restore natural colors or if the picture suddenly turned black and white. Based on information from owners of electricity appliance stores, the report estimated that 90% of those who bought color TV sets also bought the anti-mekhikon device, whose price ranged between 2,500 and 4,000 Israeli lirot (the TV set itself cost 40-50 thousand lirot).[5] Eventually, the mekhikon idea was proven to be futile, and the Israeli television stopped using it in 1980, allowing color transmissions to be received freely.

Source: Various.

 

You remember correctly. Some low cost TVs limped by with a high-Q tank that rang for an entire line (63 us).
"color killer" - haven't heard that in a while. High school was a looooooong time ago.

ak

AFAICR: they all had a high Q ring for a line period, in the UK PAL system it was connected to a PLL that brought it into lock with the alternating quadrature shift line by line - the ripple on the PLL error voltage triggered a half line rate oscillator that switched the chroma delay in or out on alternate lines.

 

I used to work on video games, there were boards with the chipsets to seperate composite to rgb video, if you have anyhone ho works with such in your area, maybe he has such a board, having the video seperated instead of having to do all that phase detection wmakes it easier. the boards were used on games that had video disks inside as well as a game board so the composite could be viewed on a standard rgb video monitor.