Don't digital monitors have DACs?

[Anarchist420]

If so, then what are the most commons DACs used? Does the DAC quality in digital monitors not really matter that much? What type of DAC does the Apple LED Cinema 24 in use?

Also, are the terms Digital-analog convertor and video encoder synonymous?

 

[Chiropteran]

I'm no expert, but DAC means digital to analog converter. If your video card is outputting a digital signal and your monitor is digital, there is no reason to ever convert anything to analog, so I don't see why the monitor would need or use a DAC.

 

[alaricljs]

LCD monitors would only have ADC circuitry if the accept an analog signal (ie: 15pin VGA) they would never have a DAC unless they have speakers and a digital audio input, but that's not what you're talking about.

Digital monitor == no DAC

 

[Anarchist420]

But don't receivers, which are hooked up digitally, have DACs?

 

[Wuzup101]

To output to analog speakers?

 

[Chapbass]

Yeah, DAC's nowadays (given the all-digital nature of monitors) are mostly used in the audio world. Speakers are analog devices. Even the "digital speakers" you buy from say logitech, are just moving the DAC into the speakers (or usually the sub) instead of the sound card.

 

[MoMeanMugs]

To output to analog speakers?

There's no such thing as a digital speaker. Everyone is clear on this, correct? Also, there might not be what you consider a DAC in an LCD monitor, but there is still analog conversion, unless you live in the Matrix and see a digital picture.

 

[alaricljs]

By analog conversion are you trying to refer to the AC->DC conversion for the power inside an LCD display? Because the signal path inside an LCD monitor is fully digital. And what I *see* is the backlight colored by the liquid crystal cells that are controlled by a digital signal. I think you might be getting a bit pedantic.

 

[dorion]

There's no such thing as a digital speaker. Everyone is clear on this, correct? Also, there might not be what you consider a DAC in an LCD monitor, but there is still analog conversion, unless you live in the Matrix and see a digital picture.

Disagree! LCD Monitors are digital, your (analog)eyes will process the digital light into whatever signal eyes communicate along the ocular nerve to the brain with.


So...
1) Apple Cinema Display does not have a DAC neither do any other newer LCDs, the new components that affect output quality are backlight and LCD type.

2) I would say they aren't. Video encoder is more of a term used for the software or hardware you would use to convert a video from one format to another(http://en.wikipedia.org/wiki/Video#Digital_encoding_formats)

 

[MoMeanMugs]

Disagree! LCD Monitors are digital, your (analog)eyes will process the digital light into whatever signal eyes communicate along the ocular nerve to the brain with.


So...
1) Apple Cinema Display does not have a DAC neither do any other newer LCDs, the new components that affect output quality are backlight and LCD type.

2) I would say they aren't. Video encoder is more of a term used for the software or hardware you would use to convert a video from one format to another(http://en.wikipedia.org/wiki/Video#Digital_encoding_formats)

Sorry to burst you bubble, but there's no such thing as digital light. By what you're saying, we have DAC's in our heads, which obviously isn't true. Are you trying to tell us you're an android?

 

[Throckmorton]

The "DAC" would be whatever converts the 8 bit value for an R, G, or B pixel into voltage to send to that pixel's liquid crystal. The liquid crystal itself can't use digital data.

 

[Mark R]

If so, then what are the most commons DACs used? Does the DAC quality in digital monitors not really matter that much? What type of DAC does the Apple LED Cinema 24 in use?

Also, are the terms Digital-analog convertor and video encoder synonymous?

The type of DAC varies in digital monitors. Cheaper monitors use cheaper DACs.

For example low end LCDs use 6-bit DACs - these can create 64 different brightness signals for the pixels - giving a total of 262,144 possible different colors. Your standard budget LCD monitor is like this (although these monitors use some tricks that can help make the images look better)

High-end LCD use 8-bit DACs, allowing the monitor to display 16.7 million colors. (The apple cinema display uses 8 bit DACs).

Pro-level LCDs use 10 (or higher)-bit DACs, allowing billions of colors (or very precise adjustment of a smaller number of colors). Most graphics cards and OSs only support 8-bit colors, so there is very little benefit in using a 10-bit monitor - only high-end graphics design, medical systems, etc. need 10-bit.

A digital-to-analog converter and video encoder are totally different things.

A DAC takes a digital signal (e.g. a number stored in RAM, which contains the brightness for a pixel), and converts it to an analog voltage (which is sent to the actual pixel on the screen).

A video encoder takes a digital signal, corresponding to many pixels. It then analyses the signal to work out what humans can see, or not - and then throws away the data it thinks humans can't see very well. The result is a stripped down digital signal which is smaller and easier to store or transmit.

 

[MoMeanMugs]

The "DAC" would be whatever converts the 8 bit value for an R, G, or B pixel into voltage to send to that pixel's liquid crystal. The liquid crystal itself can't use digital data.

This is exactly what I've been pointing out. I think people have been brainwashed by marketing terms like "digital" and "HD."

 

[postmortemIA]

This is exactly what I've been pointing out. I think people have been brainwashed by marketing terms like "digital" and "HD."

even digital signal is really analog, as it is 1 if supplied voltage is over some level, and 0 if it is lower that that...

 

[MoMeanMugs]

even digital signal is really analog, as it is 1 if supplied voltage is over some level, and 0 if it is lower that that...

That's true, although that's not always the case. A digital 1 is a negative voltage for RS-232, while a 0 is a positive voltage.