[time-nuts] ABC time signals in Tasmania/Australia wrong
Glenn Little WB4UIV
glennmaillist at bellsouth.net
Sun Jan 3 04:41:24 UTC 2010
If the TV station was transmitting digital and they were passing a
network signal, a 5 second delay is possible.
The network encodes the TV signal, then transmits it digitally.
There is a finite amount of time involved with the digital encoding
of the signal.
There is a finite delay for the transmission of this encoded signal
from the network uplink to the TV station receiver.
The TV station decodes the signal, a finite amount of time.
The TV station possibly processes the network signal, more time.
The TV station processes the output of their switcher in the
transmitter encoder, more time.
The TV station transmits the signal from the studio to the
transmitter, possibly more processing and time.
The TV receiver receives the signal and decodes it for display, more time.
With all of the processing, encoding and decoding of the digital
signal, a 5 second delay is not unheard of.
73
Glenn
WB4UIV
CE WCIV TV
At 10:56 PM 1/2/2010, you wrote:
>Hi Jim,
>
>
>In Sydney, many months ago, the ABC time signals were absent.
>I rang them and the technician explained that they use a PC program to
>produce them, and they had to reboot the computer to start them up
>again.
>So I dont know where they get the time, either off the net? or from a
>PPS signal
>from a GPS?
>Either way they do not use the old observatory signals that came from
>the PMG.
>
>A local TV station counting down to the new year was 5 seconds out!
>
>cheers, Neville Michie
>
>On 03/01/2010, at 12:14 PM, Jim Palfreyman wrote:
>
>>For the Down Under nuts,
>>
>>The ABC radio time signals in Hobart are one second out. Is it a
>>national
>>thing? Can others in the country check?
>>
>>I rang the ABC locally on xmas eve but it is still not fixed.
>>
>>Jim Palfreyman
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>
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