Re: Why is video inverted for transmission?

(snip)

I was thinking about farm houses in the plain states. Far from the big cities, and fairly flat. There could still be water towers around, though. It might be too far out for affordable cable.

I would hope that the receivers could handle simple multipath with echo cancellation systems such as those that modems or ethernet use, but for big cities it is likely too much.

-- glen

I had heard that "first generation" ATSC chipsets weren't designed to worry about multipath, but that 2nd and 3rd generation chips did. So while I think you have a very valid concern, at least the engineers were aware of the problems and I'm hoping you're going to be pleasantly surprised come 2008. :-)

My only experience with ATSC so far was in Portland, OR where about 90% of the transmitters are all on a nice, high hilltop so it was a simple matter of pointing the roof-mounted antenna that way and it all worked swimmingly.

---Joel

For some reason there is a dearth of info about it. And here I mean serious "rubber meats the road" field test results. Side by side, analog image, followed by the digital image from the same tower. Move 100ft, then do it again. And so on. Like what we do (hafta do) in medical or the FDA would read us the riot act. I know a perfect spot out here for such tests ;-)

A hill surrounded by smoothly dropping terrain is ideal for any digital comms. Multipath is hard on digital, not matter how much effort they put into FEC and all that. Same with digital cordless phones. There is no gradual decay when you walk towards the garage here, it completely cuts out from one second to the next.

--
Regards, Joerg

http://www.analogconsultants.com

You obviously have zero capacity to make valid assessments. Particularly in Usenet.

Then it ain't digital.

probably just preoccupied

wondering what the odds are that he will get together with Rosie Odonell

Also, hmmm scientology hmmm

and yet also, all those rumors he was impotent and whatever

mk5000

"The selected Company, determines which departments are available for selection"--jason smith

A lot of steel in modern barns and silos.

--
Service to my country? Been there, Done that, and I\'ve got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

They cost about 20-30 Euros over here and will be equally cheap when DVB-T hits the US.

robert

Not really. I'd call the digital artifacts "distortion" as well. Picture getting all checkered up, occasional freezes, sound dropouts etc. Still a lot less pleasant than a "snowy" analog pic.

robert

Lay off the beans and your gas may eventually go away.

Sure it ain't. But what happens if that station goes digital?

Oh well, we bought an "All in the Family" DVD at Long's so if the teevee goes dark in 2009 we'll have that ;-)

--
Regards, Joerg

http://www.analogconsultants.com

Yes. You can get a foretaste of that when the local news teams use digital feeds. What happens (a lot) is exactly what you described.

--
Regards, Joerg

http://www.analogconsultants.com

I know, but you guys had them when DTV came out. Here digital TV is on the air since years and you can't get them. The clock is ticking and there ain't many months left until early 2009. Barely 17 months.

--
Regards, Joerg

http://www.analogconsultants.com

The current plan is that the US government will give out coupons for $40 for up to two analog TV's per family. I will guess that the prices will then be $60-$70 such that we end up paying $20-$30.

-- glen

No, they gold plated the standard, so the set top box has to cope with

1080i (and downconvert it if necessary). So there will always be a lot more RAM in an ATSC decoder.

Over here, I suspect the best deal will be a DVD recorder with an ATSC tuner, where they can share some of the digital engine.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

You really don't understand how it works. The fact that you see 3 or 4 Archie Bunkers means that in a digital system, the entire datagram can easily be extracted in it's entirety.

Except that here the strength of the individual Archies varies. So in a digital datastream bits would stampede right over each other. Which ones wipe out which others depends on clouds rolling in, Fedex freighters turning onto final approach and so on. At some point any FEC scheme will just throw in the towel.

Anyway, let's see how it plays out. From what others who have tried digital TV told me things aren't looking up too much.

--
Regards, Joerg

http://www.analogconsultants.com

You ain't real bright. The FEC will get it right all the way up to over

10% bit-error-rate in current designs.

You guys must have a shit system. Your network operators should have bought the General Instrument gear. Hell, they were even able to afford it in South America!

Let's test your brightness: I wrote that the reflections are sometimes stronger than the direct path, sometimes not. When aircraft are coming through that changes in rapid flutter. What would be the bit error rate under this scenario?

Again, I don't know how it'll perform. We'll see when the converter units are on the shelves. Which I think they should have been since more than a year.

--
Regards, Joerg

http://www.analogconsultants.com