[time-nuts] lunatic fringe time standards

Bob Camp lists at rtty.us
Thu Apr 15 08:17:42 EDT 2010


If you have a THz clock rate, what ever you are using for logic will be
running "at the limit". The counter you implement would need to be a
fundamentally fast design. That limits your options. Things like Gray code
counters are inherently slower than ripple counters or Johnson counters.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Eugen Leitl
Sent: Thursday, April 15, 2010 7:42 AM
To: time-nuts at febo.com
Subject: Re: [time-nuts] lunatic fringe time standards

On Thu, Apr 15, 2010 at 07:30:27AM -0400, Bob Camp wrote:
> Hi
> I'm not 100% sure I understand exactly what you are thinking about setting

This is completely theoretical at this point. Just the required geometry
size would be prohibitive.
> My guess is that the counter needs to run at the same THz speed as 
> the oscillator. That's pretty fast. I suspect that what ever you use, 
> speed / propagation delay in the counter it's self will be an issue. 
> That will get you back to either a ripple counter or a Johnson counter. 

Wouldn't you get large errors when you caught a ripple
during readout? That wouldn't be a problem with a Gray code.
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
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