[time-nuts] Advantages & Disadvantages of the TPLL Method

Charles P. Steinmetz charles_steinmetz at lavabit.com
Thu Jun 17 15:02:12 UTC 2010

Warren wrote:

>>I'm curious how you determined that the oscillators are being held 
>>to within femtoseconds of each other.
>I done  it several ways including measuring the PD output.
>You seem to be missing how insignificant an 1-e6 injection locking 
>to EFC gain ratio is.
>I can't detail, to your satisfaction, all the hundreds of test that 
>show no significant effect of so many different things.
>For an independent test that may help you with things you missed see:

There you go again, accusing someone else of missing something.  I 
have never said I thought your method doesn't work.  I said its 
operation needs to be characterized if technically oriented folks are 
to be expected to take you seriously.  "See, it works!" is just not 
sufficient characterization to achieve this, IMO, and that is all you 
seem to offer -- references to John's tests included.  I inquired how 
you determined phase locking down to femtosecond levels, and all you 
can say is that you "measured the PD output" among other 
ways.  That's like a cosmologist saying (s)he "measured the positions 
of some stars, among other things" to determine the gravitational 
constant, which is fine for an interview in People magazine but 
inadequate for a technical audience.  What phase detector did you 
use?  What are its characteristics and limits?  With what did you 
measure its output?  What results did you get (at the very least, a 
descriptive summary of your dataset)?  How do those results support 
an inference of locking to within femtoseconds?  What other ways did 
you use to determine locking error besides measuring the PD 
output?  You imply that the ratio of the injection gain to EFC gain 
in your system is 1E-6.  How did you measure the injection 
gain?  What were the results (at the very least, a descriptive 
summary of your dataset), and how do they support an inference to the 
1E-6 figure?

Best regards,


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