Which pips?

On 10/09/2013 13:16, Dave Plowman (News) wrote:
In ,
Roger wrote:
On 10/09/2013 11:34, Dave Plowman (News) wrote:

How could you make a time signal which is sync'd to the most accurate
of sources early?


In pedantic terms you can't of course. But you could achieve the same
thing by syncing it to the source minus 2 seconds, or whatever.

Could you? You'd need the same degree of accuracy as the original source
to make this worthwhile.

I'm assuming that you can interrogate the source any time you like, and
that you don't have to wait for it to "do its thing" once an hour, or
whatever. So surely, you can detect when it's 2 seconds away (or
whatever other lead time you choose) from doing its thing.

Even if you can't, you'd only need a high degree of short-term accuracy.

The only problem is that that relies on a constant processing delay -
which is unlikely to be realised.

Quite. And even in pure analogue days, there will still be some delay
between the original signal and it reaching a listener's ears.



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Roger
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Charlie+ wrote:

Yes - and different Digital radios take differing times to decode,
If you have 6 satellite receivers running on the same channel the audio
is very weird, just slightly different delays. Very odd if you move your
head about.

Bill

In article ,
Bill Wright wrote:
Yes - and different Digital radios take differing times to decode,
If you have 6 satellite receivers running on the same channel the audio
is very weird, just slightly different delays. Very odd if you move your
head about.

You get different delays from FreeView receivers too. But DAB has the
biggest delay I've noticed. Not bothered with satellite for the pips.

--
*A cubicle is just a padded cell without a door.

Dave Plowman London SW
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In article ,
Roger Mills wrote:
Could you? You'd need the same degree of accuracy as the original source
to make this worthwhile.

I'm assuming that you can interrogate the source any time you like, and
that you don't have to wait for it to "do its thing" once an hour, or
whatever. So surely, you can detect when it's 2 seconds away (or
whatever other lead time you choose) from doing its thing.

Even if you can't, you'd only need a high degree of short-term accuracy.

I think the actual pips are only sent out every 1/4 of an hour. But I'd
not swear to it.

But if you wish to retain their accuracy, any means you used to alter them
would have to be equally as accurate - no mean task.

And just why would you bother? Who needs the time signal to be that exact
anyway at home? Just get a radio controlled clock and use that to set
others by.

Of course the delay is annoying. That's why I can have the same source in
any room in the house. ;-) Made provision for that in the '70s when I
re-wired.

--
*'Progress' and 'Change' are not synonyms.

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes
In article ,
Bill Wright wrote:
Yes - and different Digital radios take differing times to decode,
If you have 6 satellite receivers running on the same channel the audio
is very weird, just slightly different delays. Very odd if you move your
head about.

You get different delays from FreeView receivers too. But DAB has the
biggest delay I've noticed. Not bothered with satellite for the pips.

The old analogue Sky News seemed to be remarkably accurate with its
time. Their news studio clock seemed to be spot-on with the (analogue)
radio pips, and I think there should have been a delay of about half a
second. Possibly they set their clock half a second fast?
--
Ian

I think if you just remove a letter 'l' from that sentence, all is
explained !-O

On Tue, 10 Sep 2013 09:04:50 +0100, "Brian Gaff"
wrote:

I'd have thought in this day and age with such precise
clockery, that all this would be sorted, maybe sourced by theradio itself
from some synchronised signal in the transmitter.
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Hmm, well maybe, its the way that everything conforms to the standard.....
as they interpret it.
Brian

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"Java Jive" wrote in message
...
I think if you just remove a letter 'l' from that sentence, all is
explained !-O

On Tue, 10 Sep 2013 09:04:50 +0100, "Brian Gaff"
wrote:

I'd have thought in this day and age with such precise
clockery, that all this would be sorted, maybe sourced by theradio itself
from some synchronised signal in the transmitter.
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On Mon, 09 Sep 2013 17:10:28 -0500, "Steve Thackery"
wrote:



To summarise: the FM pips. The DAB pips are delayed because your DAB
radio takes a certain time to decode the signal.

I understood the 'official' pips were on long wave and that FM was
delayed albeit nothing like as much as DAB.

On 10/09/2013 18:41, Scott wrote:
On Mon, 09 Sep 2013 17:10:28 -0500, "Steve Thackery"
wrote:



To summarise: the FM pips. The DAB pips are delayed because your DAB
radio takes a certain time to decode the signal.

I understood the 'official' pips were on long wave and that FM was
delayed albeit nothing like as much as DAB.

Surely the propagation delays on FM would be the same as AM?
--
Phil Cook

In message , Scott
writes
On Mon, 09 Sep 2013 17:10:28 -0500, "Steve Thackery"
wrote:



To summarise: the FM pips. The DAB pips are delayed because your DAB
radio takes a certain time to decode the signal.

I understood the 'official' pips were on long wave

That could well be so. Although there are two fill-in transmitters in
Scotland, Droitwich LW is directly receivable over all of the rest of
the UK, so reception times will be almost simultaneous. However, the
delays on the audio feeds to all the other transmitters (LW and FM) will
vary (especially if carried on telephone lines, and less so on fibre),
so depending on their path lengths, the delays would vary quite a bit (a
few milliseconds?).

and that FM was
delayed albeit nothing like as much as DAB.



--
Ian