[ntp:questions] Re: Clock accuracy & auto setting : digital televisiondoes a crap job of providing time services...
mikehack at u.washington.edu
Sat Apr 29 01:54:22 UTC 2006
No -- I am not suggesting upgrading the NTP model, but having 64 extra bits
around can help futureproof a signal -- and provide other services. Plain
NTP is fine for computer networks, but for broadcast TV and radio -- extra
bits could be used to increase the value of the NTP time information...
> This probably belongs more in the NTP WG and/or hackers than here since
> it sounds like you are looking for enhancements to the NTP model.
> Max Power wrote:
>> In North America, the FM RDS time service is of very low quality.
>> In Europe (I understand) this is not the case with RDS.
>> Stations running RDS should be mandated by law to provide a quality
>> service -- based on transmitter power and coverage area.
>> Over time RDS's time service should be uniform.
>> DRM (on MW and SW) time service is of a lower quality than RDS -- but
>> be upgraded with a specialized "80 bit" NTP-UNIX time packet.
>> ATSC and DVB-T (& DVB-H/M) need a uniform ~"80 bit"...~"128 bit" time
>> service that is well thought out.
>> Futureproofing is important, so probably 128 bits or more is preferable.
>> LF time services are OK, and are necessary over large transnational
>> regions -- like Sub Saharan Africa, Australasia and South America ... but
>> any new LF service needs to be more technologically advanced than WWVB,
>> or DCF77 and its Swiss twin. In these regions 10 LF frequencies need to
>> allocated, but the signal to be transmitted needs to be more modern than
>> WWVB or DCF77 -- maybe using some form of low complexity PSK or low
>> complexity QAM and 240 hz to 480 hz of bandwidth. The signal must be
>> futureproofed -- as above.
>> I wish I had all of the email addresses of the Canadian National Research
>> Council -- so that I could email them my CHU upgrade proposal at
>> * http://CBC.am/CHU.htm
>> * This proposal probably, if implemented -- would require a signal
>> to account for 2 transmitters on all of the frequencies used.
>> * A properly designed signal upgrade could make CHU a more powerful
>> [technological design] than WWV[H] -- but this would probably require 2
>> or 3
>> years of experimentation. I would love to see support for high speed ECC
>> polytone and MD63 (MD?) with its Walsh coding.
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