[time-nuts] New WWVB format...

Don Latham djl at montana.com
Wed Sep 26 18:59:55 UTC 2012


This is a job for Raspberry Pi...
Don

Majdi S. Abbas
> On Wed, Sep 26, 2012 at 10:13:22AM -0700, Tom Van Baak wrote:
>> My reading of the document(s) is that the new format will in fact
>> allow
>> WWVB to be used as a frequency standard with even greater precision
>> then
>> before, though not with unmodified legacy WWVB carrier receivers. My
>> hope
>> is that one of you will produce a clever reference design for such a
>> T&F
>> receiver make it available to the group. It sounds like a very fun DSP
>> project; one that we can all learn from. Bonus points for making it an
>> open-source Arduino shield. Making it work with both DCF77 and WWVB
>> would
>> also be a plus.
>
> 	DSP would be good, although I also think an microcontroller
> implementation could be interesting.  Atmel's ARM MCUs look like they'd
> be good candidates for this sort of thing.  (Pretty fast, enough storage
> to do interesting things with it, and a fast enough ADC for 60 KHz.)
>
> 	I've got a couple of these that I might use as a development
> platform:
>
> 	https://www.olimex.com/Products/ARM/Atmel/SAM7-P256/
>
> 	Has anyone come up with a reasonable algorithm to implement in
> a microcontroller?  (DSP development kits are a bit more spendy than I'd
> like to invest in a prototype. :)
>
>> If nothing else, a well-documented hack for existing Spectracom and HP
>> WWVB receivers would be welcome. A third idea is a translator that
>> receives the new carrier format and re-transmits the old carrier
>> format;
>> that way no mods need to be made to legacy WWVB receivers at all,
>> regardless of age. It would be similar to the way the G2G (GPS to
>> GOES)
>> translator worked. Extra credit for adding back the 45 degree hourly
>> phase shift.
>
> 	I'm not sure I want the phase shift back.  Some references
> don't handle it gracefully.
>
> 	That said, I have the following victims (time interval and TOD):
> 		- TrueTime 60DC and 60LF
> 		- Spectracom Netclock/2
>
> 	As far as I'm concerned I'm willing to modify any of these at
> this point.  I've got a rough idea how to modify the 60DC: seems like
> you could double the 60 KHz LO after the IRIG output divisor chain, as
> it's headed into the PLL, and double the incoming signal after the RF
> amp.  This is convenient since it's running between assemblies, anyway.
>
> 	Does anyone have a manual or schematic for the 60LF?  I could
> probably figure it out, but it'll be easier with documentation.
>
> 	Thoughts on modifications are welcome, I'd even be happy to compile
> them all into a public list somewhere.
>
> 	--msa
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>


-- 
"Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind."
De Erroribus Medicorum, R. Bacon, 13th century.
"If you don't know what it is, don't poke it."
Ghost in the Shell


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com





More information about the time-nuts mailing list