Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [tv]

Use this tag for technical aspects of TV (video formats, for example). Shopping questions are off-topic and repair questions might be too localized.

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How did old television screens with a light grey phosphor create the darker contrast parts of the display?

Many old television screens have a very prominent "light grey" color to the glass, I'm guessing from the phosphor, create darker areas if the effect of electrons make the phosphor glow? Is it an illusion due to contrast between the brightly lit and…
Zhro
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Why are color difference signals transmitted rather than R,G,B signals?

In color television systems back in the early days, people used to transmit color difference signals (Y-R) and (Y-B) along with Y, which is the luminance signal. My question is why are color difference signals transmitted rather than just two of the…
Moonzarin Esha
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Generating PAL tv signal using a PIC

I'm trying to generate PAL tv signals using a PIC24FJ64GB002 using a similar method to the circuit described half way down this page. The only difference is that my circuit needs to run at 3v instead of 5v due to using a PIC24 so I've recalculated…
John Burton
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Why do CRT TVs need a HSYNC pulse in signal?

Could someone, please, explain how old CRT TVs reacted to input signal, specifically to VSYNC and HSYNC pulses? Do these pulses control the electron beam? For instance, if signal would consist only of VSYNC pulses, would the beam stay at its initial…
Scylurus
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Circuitry of TV splitters

I'm trying to understand the circuitry of TV signal splitters and associated boosters/amplifiers, and I have two questions. My situation is as follows. I have a TV aerial (antenna) in my loft. It connects to a non-powered box, which I assume must…
seglea
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TV screen in still photo: Why are there dark, blackish bands?

I was trying to capture the scanning process of a CRT TV screen in a photo. It gave me these dark, broad bands, shown below: Fig. 1 a,b,c I'm trying to understand the cause for this banding. However, I couldn't understand it clearly in very similar…
Always Confused
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"shark teeth"-like PCB feature in high voltage section of modern HDTV

I found this tooth-like non-masked, solder-covered trace pattern on modern single board HDTV. It's in the 120VAC "HOT" section of the switch-mode PS. Looks like some sort of spark gap or protection feature. There are two of them, one with 3 "teeth"…
Christopher Allen
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What are these wiry protrusions on a TV antenna?

This photo shows part of a large antenna assembly which has a series of thin wire protrusions: (Source) This antenna is apparently used for TV transmission. What are those protrusions for? I'm guessing something to do with lightning or static? The…
StayOnTarget
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Why the audio subcarrier is never transmitted with baseband analogue video signal?

In the era of analogue video, when you needed to connect a local video source (STB, VCR, game console, DVD player, etc.), the most ubiquitous way to do so, next to using an RF modulator, would be to use a composite video connection. But it only…
kFYatek
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Why is an HDMI signal causing interference with Over-The-Air digital television?

I do not have cable or satellite television so I rely on Over-The-Air digital programming (free) and Internet streaming services to provide entertainment. A couple years ago, I purchased a video card for my desktop PC which provides simultaneous…
digitale
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What is the function of "Picture tube charger"?

There is a bizzare device called picture tube charger or CRT-Charger. Here I attach the some diagrams of it from a circuit-book. Now, what is its function? what changes it create inside the CRT? such- as, Is it a method to reverse the…
Always Confused
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Is my LCD TV doing some sort of dithering?

I'm using a 32" 'LED' TV as a monitor (1920x1080 over HDMI). I've been noticing some annoying horizontal stripes where the source is displaying grey pixels. It seems that what's happening is the TV is using multiple dots/sub-pixels vertically for…
CupawnTae
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Is it possible to combine independent digital TV antennas?

Is it possible to create a TV antenna that is composed of smaller antennas that are pointed to different broadcast centers? So in essence, many antennas for just a single digital TV. Is it possible without any problem? or It is possible but with…
Abel Melquiades Callejo
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Could an analog TV signal be transmitted over broadcast RF from a composite cable somehow?

My understanding is that an analog video signal (PAL or NTSC) has a particular form/structure. That signal can be transmitted over the airwaves at a particular frequency, & multiple analog TV signals can be transmitted at different…
Duke Dougal
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How do LCD screens repair themselves?

Hey, electronics people: A few months ago, I cleaned a spot on an LCD flat screen. Whatever it was, it was stuck on there pretty good and I guess I pushed down on it too hard (actually wasn't hard at all, to be honest). Anyway, next time I turned it…
voices
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