No matter what you’ve heard, there are always good and bad points to any technology. The transition to digital is no different. Let’s at least mention some of the good points before we talk about the bad parts of this whole digital thing.
Better picture quality is the most notable and easily visible quality of the Digital delivery system over Analog
I’m sure you’ve already heard some of the hype surrounding the transition. Most of what the sales people focus on is the picture quality and I really can’t fault them for that. The quality, (even in the lower resolution of digital and HD picture quality) is much better than the old analog broadcast and it should be. It generally has a minimum of twice the resolution.
So what does that mean? It means that there are more lines in the picture. (More lines generally translates to mean better picture quality.) The old analog signal only has around 250-265 lines. The new signal generally has a minimum of 480. Another thing you will notice when people talk about the lines of resolution is either a thing called “i” or “p” after the listed number of lines, (480i, 720i, 720p, 1080i, 1080p…etc). The “i” stands for interlaced scan and the “p” stands for progressive scan. In this article I won’t get into the technical discussion of the two. I really just want you to understand a little more about the nomenclature most widely used. (I’ll save the other discussion for another day. Who knows, I may even bring in a friend to explain it to us better than I can.) (We’ll see what happens…but…I promise it will be sooner than later.)
So why do I mention all this technical stuff, anyway? I don’t know for sure, but I guess it’s just the technician in me. (You’ll find I also have the tendency to build a person a clock when they ask me what time it is.)
Without getting too technical, what if someone mentions to you the quality of a program they are watching and they say, “this program is in 480 i, what does that mean?” You can tell them, “It means that there are four hundred and eighty lines of resolution and it is interlaced.” (Wow, don’t you just love the power you now have to make that statement.)
In reality, I think most of you are probably saying, “So what does all of this mumbo, jumbo mean?”
Since it is easier to show than to tell, I would like you to check out what I consider a really good illustration comparing the two at:
< http://en.wikipedia.org/wiki/Progressive_scan >
This will help you understand the two types of scan delivery we see on our TVs the most. A full understanding of television is a much more involved process than I want to offer here, but at least, after visiting that link, you may understand the difference between the two types of scan a little better. (Besides, I fully understand that most people just want to watch their TVs, not know how to build them.)
Interlacing is still necessary today and solved a big signal delivery problem early on in television broadcasts. It was the norm for many years. Progressive scan does not fully replace older technology, but, it does hold a strong place in the new way of delivering pictures to people along the different avenues into peoples’ homes and especially over the internet.
With Digital delivery you can fit more into less …
Aside from greatly improved picture quality, another good thing about digital signal delivery is that you can fit more into less. That sounds like a strange statement I know, but, it is true.
Let’s talk about a little thing called available bandwidth. The new digital signals allow stations to offer more in the same amount of bandwidth than analog did. If you’ve had the chance to observe some of the new Television signals, you have probably been a little confused by all of the similar numbers that you find.
As an example I want to use the Naples-Fort Myers DMA local NBC and PBS broadcasts. If you tune your TV or converter box to channels 20-1 and 20-2 you will notice the similarity between the two. 20-1 is the main DTV/HD channel for their local and network programming. You will notice that 20-2 is now called their 2 News Now channel. It is in the same signal as their 20-1 but because of the digital technology, can carry different programming entirely.
There are limitations to the use of their available bandwidth that are dictated by the amount of information they use up with their broadcasts. To simplify, they could possibly broadcast at least up to six channels in their available bandwidth but not all six could be HD channels.
My second example is the local PBS affiliate. If you turn to their channel 30-1 you will find their main broadcast of DTV/HD. Change the channel up to 30-2 and you will find what they now call PBS World. It is generally separate programming from 30-1 and can also be in HD. Their next channel is 30-3 and they call it PBS Create. It is also separate programming from the other two. That brings us to the final example of their channels 30-4. At the present, this is a lower resolution channel and contains what they call FKN/FLC and carries programming from Florida Schools (Florida Knowledge Network) and the Florida Government Channel (FLC).
As you can see the broadcasters are able to supply more programming in the same amount of bandwidth which is called one channel. This means the consumer has more programming available to watch and it actually only takes up one channel slot of bandwidth. Admittedly, the new signal is 3 mHz wider than the old Analog signal (it is 9 mHz wide as opposed to 6 mHz) but this is one of the good advantages of the new digital broadcast spectrum.
With Digital there is less visible interference …
One of the great advantages of digital signal delivery is the absense of snow and ghosting. This is a mixed blessing. In one sense, you should always have clearer pictures because there should be no snowy interference and there should be no ghosting (multi-path) in the picture. In another sense, it could be that because there is such strong multi-path interference, you may not be able to receive a channel’s signal at all, (at least well enough to see a picture). (We’ll talk more about that in part 3, “the Bad”).
Wow! There sure is lot of stuff to talk about when it comes to THE DIGITAL TRANSITION; What do you think? I think we could go on and on, but I also think we will have more on Thursday… so … check back then and hear more on this Digital Transition stuff. That’s where I give my opinion of what I think is bad about the Transition. (Trust me, I won’t be too rough on it ’cause I really like it … well … mostly, anyway.
If you would like to know a little more technical info (and I stress the word technical) about DTV check out the link below:
< http://en.wikipedia.org/wiki/Digital_television >
There is some really great info on that link …
Hey… this is Russ and:
I’ll see you next time…
© February 2009 – all rights reserved
Norman TV & Video Systems and