smgemelos
12-02-2005, 03:05 PM
I am trying to figure out if there is a benefit for going digital versus analog to drive an HDTV. I read an article from Blue Jeans Cables, and they made arguements for and against each type.... Component and HDMI/DVI....
Being an electrical engineer, and having worked on high bitrate board design and transmission systems, I have some knowledge on analog and digital transmission, and issues related to the cable and it's impact on cables....
but I still have some opinions and some questions, and I would like ot see how it jives with you all...
We are starting with a digital format - assuming we are using a DVD or HD receiver as the source. For short cable runs the cable noise is minimal (assuming a good quality cable), most of the noise and distortion in introduced each time the signal is converted from digital-to-analog (D-A) or analog to digital (A-D) it is degraded... either electronic noise in the D-A converter, or quantization noise in the A-D converter. So we want to minimize the number of times we make these conversions.
So if we have a digital display - plasma, LCD, or DLP - we should avoid analog completely, avoid adding any additional noise to the signal... what comes out of the MPEG decoder goes straight to the display. It would be foolish to use component cables for a digital display - you are using the D-A converters in the source to create and analog signal, an then the A-D converters in the display to present the image.
If we have a analog display - any tube based display - we sould minimize the number of D-A and A-D conversion.... and there should only be one, converting from digital to analog for presentation on the display. And we should choose the best D-A converter in the system. If the source has the better D-A converter, use that converter and drive the display with component video cables. If the display has the better D-A converters, use HDMI or DVI cables from the source to the display.
This is my understanding of all this from an engineer's point of view.... What's your take on this?
Being an electrical engineer, and having worked on high bitrate board design and transmission systems, I have some knowledge on analog and digital transmission, and issues related to the cable and it's impact on cables....
but I still have some opinions and some questions, and I would like ot see how it jives with you all...
We are starting with a digital format - assuming we are using a DVD or HD receiver as the source. For short cable runs the cable noise is minimal (assuming a good quality cable), most of the noise and distortion in introduced each time the signal is converted from digital-to-analog (D-A) or analog to digital (A-D) it is degraded... either electronic noise in the D-A converter, or quantization noise in the A-D converter. So we want to minimize the number of times we make these conversions.
So if we have a digital display - plasma, LCD, or DLP - we should avoid analog completely, avoid adding any additional noise to the signal... what comes out of the MPEG decoder goes straight to the display. It would be foolish to use component cables for a digital display - you are using the D-A converters in the source to create and analog signal, an then the A-D converters in the display to present the image.
If we have a analog display - any tube based display - we sould minimize the number of D-A and A-D conversion.... and there should only be one, converting from digital to analog for presentation on the display. And we should choose the best D-A converter in the system. If the source has the better D-A converter, use that converter and drive the display with component video cables. If the display has the better D-A converters, use HDMI or DVI cables from the source to the display.
This is my understanding of all this from an engineer's point of view.... What's your take on this?