[time-nuts] Different Thunderbolt versions
bruce.griffiths at xtra.co.nz
Thu Feb 26 07:04:16 UTC 2009
SAIDJACK at aol.com wrote:
> Hi Bruce,
> seems that would be in line with extending the 10s plot down to 1s in a
> linear fashion.
> Not that great. Tom's GPSDO measurements show some GPSDO's go down to ~E-013
> at 1s.
> In a message dated 2/25/2009 12:33:22 Pacific Standard Time,
> bruce.griffiths at xtra.co.nz writes:
> Specified Allan deviation is 2E-11 @1s.
That isnt a great advantage in this application given that the
contribution of the ionosphere to the VLBI receiver output signal phase
noise is around 8E-11 @ 10s at 50MHz.
Typically in VLBI integration times op up to 10,000 seconds or more are
used. Integration times shorter than 100 sec are not usually of much
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