What causes ghosting on digital transmissions?
 

I've noticed that with my Goodmans GDB2 box I am getting a 'ghost'
around features in the picture. My aerial is almost line of sight with
Emily Moor, and is about 10 yrs old.

Where should I be looking to remove the artifacts, aerial or a better
STB? I've tried putting an amp in the downlead but ti no avail. All
advice gratefully accepted.

Where should I be looking to remove the artifacts

Digital cable or satellite. Anything with a higher bit rate really! ;)

If you mean ghosting in the sense of a repeated 'shadow' as seen on analogue
TV, then this is being generated by signal reflections in the analogue path
between your box and your TV (including the circuits *inside* the boxes!).
If you're connecting via SCART, try a different lead. If you're connecting
via S-Video try via SCART (or vice-versa). You need to see if you can change
the connection between box and TV somehow.

If you mean blocks or artefacts in the picture, then welcome to the world of
digital TV. 'They' will try to tell you it gives a better picture than
analogue TV, just like the hype that digital radio sounds better than FM!

Cheers,
Dan.

"Dan Wood" wrote

snip

If you mean blocks or artefacts in the picture, then welcome to the world
of
digital TV. 'They' will try to tell you it gives a better picture than
analogue TV, just like the hype that digital radio sounds better than FM!

*****

Not a very good analogy, I think. DAB - as transmitted in the U.K. - is
intrinsically worse quality than FM on nearly all channels because of the
low bit-rates used. In most real-world locations and with most real-world
set-ups, both analogue and digital tv can have faults - but the faults are
different and one type of fault may be preferable to another according to
individual taste.

Because I live in a dip, and because I choose to have my tv aerial in the
loft, my analogue tv is less than perfect and teletext can suffer a little.
Digital tv has the odd glitch which I tolerate because otherwise the quality
of the picture is better than analogue. And, of course, if you want
wide-screen you have to have digital, and if you want BBC4 you have to have
digital.

André Coutanche

wrote in message
...
I've noticed that with my Goodmans GDB2 box I am getting a 'ghost'
around features in the picture. My aerial is almost line of sight with
Emily Moor, and is about 10 yrs old.

Where should I be looking to remove the artifacts, aerial or a better
STB? I've tried putting an amp in the downlead but ti no avail. All
advice gratefully accepted.



Can you describe this ghosting in a bit more detail ? Traditional ghosting,
that is with ghost image/s displaced to the right of the main image does
not occur with DTT signal. So your artefacts are not created by multipath
reflections.

If this ghosting is a kind of ringing around the outlines in the picture the
first thing to do is to reduce the sharpness control on the TV to zero. I
assume that you are using a scart connection and that the box and TV are
both in RGB mode.

come back with some more details.

Richard.

I've tried putting an amp in the downlead but ti no avail.

To cure "ghosting"??? Hee hee hee! ****!


------------------------------------------
The Bristol, UK branch of the Renaldo & The Loaf fan club

http://english.aljazeera.net

All the connections are by high quality scart. the TV is a 10 yo sony
KVX series with RGB input to the scart. I have just changed the output
from the GDB2 from RGB to CVBS (?) and hey presto the halo has gone,
and thwe picture is much brighter.

In more detail the halo effect was most pronounced with higher
contrast images, so a bald head on a dark background would have a
second bald head displaced by 5 mm to the right.

On Thu, 2 Sep 2004 09:47:07 +0000 (UTC), "Richard"
wrote:


wrote in message
.. .
I've noticed that with my Goodmans GDB2 box I am getting a 'ghost'
around features in the picture. My aerial is almost line of sight with
Emily Moor, and is about 10 yrs old.

Where should I be looking to remove the artifacts, aerial or a better
STB? I've tried putting an amp in the downlead but ti no avail. All
advice gratefully accepted.



Can you describe this ghosting in a bit more detail ? Traditional ghosting,
that is with ghost image/s displaced to the right of the main image does
not occur with DTT signal. So your artefacts are not created by multipath
reflections.

If this ghosting is a kind of ringing around the outlines in the picture the
first thing to do is to reduce the sharpness control on the TV to zero. I
assume that you are using a scart connection and that the box and TV are
both in RGB mode.

come back with some more details.

Richard.

In article ,
writes
All the connections are by high quality scart. the TV is a 10 yo sony
KVX series with RGB input to the scart. I have just changed the output
from the GDB2 from RGB to CVBS (?) and hey presto the halo has gone,
and thwe picture is much brighter.

In more detail the halo effect was most pronounced with higher
contrast images, so a bald head on a dark background would have a
second bald head displaced by 5 mm to the right.

Sounds like something funny in the TV's RGB implementation. RGB modes
can be a bit idiosyncratic sometimes.
--
Tim Mitchell

No Polly, so I can have a telly in another room, but I also noticed
that it made no difference to the ghosting.

Having now switched the output from RGB to CVBS, having the amp inline
or out DOES make a difference in that there is sharper edge around
contrasted objects, and just a hint of white lining.

(And no, not as in 'the middle of the road' before you mention it.)

On 02 Sep 2004 11:05:40 GMT, ( Polly Prissypants)
wrote:

I've tried putting an amp in the downlead but ti no avail.

To cure "ghosting"??? Hee hee hee! ****!


------------------------------------------
The Bristol, UK branch of the Renaldo & The Loaf fan club

http://english.aljazeera.net

having the amp inline
or out DOES make a difference in that there is sharper edge around
contrasted objects,

If it is indeed "ringing" then it is faulty!


------------------------------------------
The Bristol, UK branch of the Renaldo & The Loaf fan club

http://english.aljazeera.net