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Digital drop out.



 
 
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  #11  
Old December 4th 16, 08:41 PM posted to uk.tech.digital-tv
Roderick Stewart[_3_]
external usenet poster
 
Posts: 2,172
Default Digital drop out.

On Sun, 04 Dec 2016 16:21:34 +0000 (GMT), Jim Lesurf
wrote:

As I understand it, it is delays due to the processing of the digital
signal. Different sets may have different delays, and radio and TV may
have even more different delays. FM radio would have given you Big Ben
accurately, but nothing digital is likely to have done.


Strictly speaking FM uses NICAM for distribution, and NICAM is "digital".
It does add a delay, but I doubt you'd notice it. So your "nothing" aims at
the wrong target. The cause is the lossy compression schemes employed for
'digital' TV and radio which the systems take some time to process. Not
"digital" per se.


Presumably the compression for video takes considerably longer than
for audio, but the audio part of a television broadcast has to be
delayed to match the picture. Audio on its own, i.e. radio, wouldn't
need so much so the delay wouldn't be noticeable.

I first became aware of how much delay must be in the system on the
day of Princess Diana's funeral, when every channel (except 4) was
broadcasting the same material, and the difference between the latest
and earliest version was about 8 seconds. The only time you can trust
is either a radio controlled clock or the internet. Broadcasting used
to be an authoritative source for everything but not any more.

Rod.
  #12  
Old December 5th 16, 02:43 AM posted to uk.tech.digital-tv
Bill Wright[_3_]
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Posts: 2,084
Default Digital drop out.

On 04/12/2016 18:08, Mark Carver wrote:
On 04/12/2016 17:22, Bill Wright wrote:
On 04/12/2016 16:39, Mark Carver wrote:

NICAM itself adds a delay of around 14ms.



It's near instantaneous then?


Yes, 14ms near !


14ms? That's about two foot innit? I'll never get the hang of this new
money.

Bill
  #13  
Old December 5th 16, 03:07 AM posted to uk.tech.digital-tv
Bill Wright[_3_]
external usenet poster
 
Posts: 2,084
Default Digital drop out.

On 04/12/2016 20:41, Roderick Stewart wrote:

Broadcasting used
to be an authoritative source for everything but not any more.


That's a fallacy. They always spun us a yarn. The difference is we've
got the internet now. It the BBC or any of them said water was H2O I'd
check on the internet.

Bill

  #14  
Old December 5th 16, 09:24 AM posted to uk.tech.digital-tv
PeeGee
external usenet poster
 
Posts: 156
Default Digital drop out.

On 04/12/16 20:41, Roderick Stewart wrote:
On Sun, 04 Dec 2016 16:21:34 +0000 (GMT), Jim Lesurf
wrote:

As I understand it, it is delays due to the processing of the digital
signal. Different sets may have different delays, and radio and TV may
have even more different delays. FM radio would have given you Big Ben
accurately, but nothing digital is likely to have done.


Strictly speaking FM uses NICAM for distribution, and NICAM is "digital".
It does add a delay, but I doubt you'd notice it. So your "nothing" aims at
the wrong target. The cause is the lossy compression schemes employed for
'digital' TV and radio which the systems take some time to process. Not
"digital" per se.


Presumably the compression for video takes considerably longer than
for audio, but the audio part of a television broadcast has to be
delayed to match the picture. Audio on its own, i.e. radio, wouldn't
need so much so the delay wouldn't be noticeable.

I first became aware of how much delay must be in the system on the
day of Princess Diana's funeral, when every channel (except 4) was
broadcasting the same material, and the difference between the latest
and earliest version was about 8 seconds. The only time you can trust
is either a radio controlled clock or the internet. Broadcasting used
to be an authoritative source for everything but not any more.

Rod.


I'm not convinced I trust a radio controlled clock - mine has shown the
time as 36:99 (or some symbols for minutes larger than 100), but usually
during maintenance and at a time when you might want a wake-up alarm. I
don't recall a problem before the change of transmitter location. The
German transmitter is far more reliable!

--
PeeGee

"Nothing should be able to load itself onto a computer without the
knowledge or consent of the computer user. Software should also be able
to be removed from a computer easily."
Peter Cullen, Microsoft Chief Privacy Strategist (Computing 18 Aug 05)
  #15  
Old December 5th 16, 12:34 PM posted to uk.tech.digital-tv
James Heaton
external usenet poster
 
Posts: 98
Default Digital drop out.


"PeeGee" wrote in message
o.uk...
On 04/12/16 20:41, Roderick Stewart wrote:
On Sun, 04 Dec 2016 16:21:34 +0000 (GMT), Jim Lesurf
wrote:

As I understand it, it is delays due to the processing of the digital
signal. Different sets may have different delays, and radio and TV may
have even more different delays. FM radio would have given you Big Ben
accurately, but nothing digital is likely to have done.

Strictly speaking FM uses NICAM for distribution, and NICAM is
"digital".
It does add a delay, but I doubt you'd notice it. So your "nothing" aims
at
the wrong target. The cause is the lossy compression schemes employed
for
'digital' TV and radio which the systems take some time to process. Not
"digital" per se.


Presumably the compression for video takes considerably longer than
for audio, but the audio part of a television broadcast has to be
delayed to match the picture. Audio on its own, i.e. radio, wouldn't
need so much so the delay wouldn't be noticeable.

I first became aware of how much delay must be in the system on the
day of Princess Diana's funeral, when every channel (except 4) was
broadcasting the same material, and the difference between the latest
and earliest version was about 8 seconds. The only time you can trust
is either a radio controlled clock or the internet. Broadcasting used
to be an authoritative source for everything but not any more.

Rod.


I'm not convinced I trust a radio controlled clock - mine has shown the
time as 36:99 (or some symbols for minutes larger than 100), but usually
during maintenance and at a time when you might want a wake-up alarm. I
don't recall a problem before the change of transmitter location. The
German transmitter is far more reliable!


So long as you remember to fit an offset to the clocks before you sell them
in a different time zone that is...

http://www.dailymail.co.uk/news/arti...our-ahead.html

James

  #16  
Old December 6th 16, 10:03 AM posted to uk.tech.digital-tv
Indy Jess John
external usenet poster
 
Posts: 1,240
Default Digital drop out.

On 05/12/2016 12:34, James Heaton wrote:

wrote in message
o.uk...


I'm not convinced I trust a radio controlled clock - mine has shown the
time as 36:99 (or some symbols for minutes larger than 100), but usually
during maintenance and at a time when you might want a wake-up alarm. I
don't recall a problem before the change of transmitter location. The
German transmitter is far more reliable!


So long as you remember to fit an offset to the clocks before you sell them
in a different time zone that is...

http://www.dailymail.co.uk/news/arti...our-ahead.html

James

My Sister-in-law bought a Lidl clock and it was always an hour fast and
there was no option to tell it to use UK time. Lidl offered her the
money back if she brought the clock back.

I removed the hour hand and replaced it back an hour, and it has been
perfect ever since.

Having said that, my wife's bedside clock radio usually shows the right
time but a few times a year it resets to 4 hours early. It corrects
itself the following night. I can only assume that it misreads a
transmission occasionally.

Jim

  #17  
Old December 6th 16, 10:35 AM posted to uk.tech.digital-tv
Andy Burns[_12_]
external usenet poster
 
Posts: 443
Default Digital drop out.

Indy Jess John wrote:

James Heaton wrote:

http://www.dailymail.co.uk/news/arti...our-ahead.html

My Sister-in-law bought a Lidl clock and it was always an hour fast and
there was no option to tell it to use UK time.


Are you absolutely /certain/ of that? The recent one for sale in Lidl
had people claiming it couldn't be offset to UK time, when a few seconds
RTFM proved it could.
  #18  
Old December 6th 16, 12:48 PM posted to uk.tech.digital-tv
James Heaton
external usenet poster
 
Posts: 98
Default Digital drop out.


"Andy Burns" wrote in message
...
Indy Jess John wrote:

James Heaton wrote:

http://www.dailymail.co.uk/news/arti...our-ahead.html

My Sister-in-law bought a Lidl clock and it was always an hour fast and
there was no option to tell it to use UK time.


Are you absolutely /certain/ of that? The recent one for sale in Lidl had
people claiming it couldn't be offset to UK time, when a few seconds RTFM
proved it could.


The one I referenced was about 12-18 months ago; Lidl offered refunds on
them rather than telling people to RTFM so suggests there wasn't a way of
doing it. Other than IJJ's innovative method upthread...

Probably the more recent one you refer to had an offset feature in response
to this...

James

  #19  
Old December 6th 16, 12:51 PM posted to uk.tech.digital-tv
Indy Jess John
external usenet poster
 
Posts: 1,240
Default Digital drop out.

On 06/12/2016 10:35, Andy Burns wrote:
Indy Jess John wrote:

James Heaton wrote:

http://www.dailymail.co.uk/news/arti...our-ahead.html

My Sister-in-law bought a Lidl clock and it was always an hour fast and
there was no option to tell it to use UK time.


Are you absolutely /certain/ of that? The recent one for sale in Lidl
had people claiming it couldn't be offset to UK time, when a few seconds
RTFM proved it could.


Yes I am certain. I read the manual and I also read the relevant
threads in various forums (which is where I found the instructions on
how to get it apart to remove the hands). That particular clock did not
have any capability to change the source of the time signal (which
probably explains why Lidl was offering customers their money back
rather than providing instructions).

Jim

  #20  
Old December 6th 16, 04:30 PM posted to uk.tech.digital-tv
Paul Ratcliffe
external usenet poster
 
Posts: 2,473
Default Digital drop out.

On Mon, 5 Dec 2016 02:43:19 +0000, Bill Wright
wrote:

NICAM itself adds a delay of around 14ms.

It's near instantaneous then?


Yes, 14ms near !

14ms? That's about two foot innit?


No it's about 14 feet. 1 foot = 1 millisecond for most practical
purposes.
 




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