[time-nuts] FE-.5680A trimming resolution

Chris Albertson albertson.chris at gmail.com
Mon Jan 30 14:52:05 EST 2012

On Mon, Jan 30, 2012 at 10:43 AM, Mark Sims <holrum at hotmail.com> wrote:
> These are 4-BYTE single precision floating point numbers,  not 4 bit integers.   They are the values plotted in the Lady Heather PPS and OSC graphs....

Sorry I type faster than I think.  You are right they can't be four bits.
I work in rocket telemetry,  you'd think I'd get this straight. I
write software to unpack this kind of stuff.

>  A much better approach is to minimize the system errors with a GOOD antenna,   accurate position survey,   proper oscillator control parameters,   and temperature stabilization (of both the receiver and power supply)...   Lady Heather is willing to oblige on the last points.   A good Tbolt implementation can get the PPS plot to under a few nanoseconds of error.

I've done this.  I see values in the single digit nanoseconds.  I have
a timing antana on a mast on the roof.  Perhaps I could get a better
timing antenna and low loss coax lead.  LH reports the signal at 40dB,
+-2dB.  Is that good enough?

I've seen adev plots from an Oncore MT12
(www.leapsecond.com/pages/m12-adev/)  where these error estimates are
added in or not and they get maybe 20%  better with the corrects
applied.    the MT12 produces error estimates about that same size as
a T-bolt.

The data looks noisy on LH's graph because of the scale of the graph.
Compared to the 1PPS it is a smooth function.

Chris Albertson
Redondo Beach, California

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