[time-nuts] STEL-1173/CM Source

Ed Palmer ed_palmer at sasktel.net
Sat Nov 15 10:38:45 EST 2014

Yes, I'm sure.  I did check the cabling. :)  If I was somehow measuring 
the Tbolt or 4065A against itself, there wouldn't be any frequency offset.

The Oscilloquartz 3210 (which appears to be an OEM'd 4065A) is spec'ed 
at 3E-13 @ 100K seconds.  The 4065C is even better at 8.5E-14 with a 
noise floor of 5E-14.

My data run is continuing.  The end of the graph is flopping around as 
usual, but it's now showing Total Deviation of about 1.4E-13 @ 100K 
seconds with a total of 226 800 readings at 1 second intervals. 
Frequency offset error is still 6E-13.  Autocorrelation of the results 
shows diurnal spikes at approximately 86 160 and 172 310 seconds (i.e. 
one and two sidereal days).


On 11/14/2014 11:00 AM, Azelio Boriani <azelio.boriani at gmail.com> wrote:

> Are you sure you are measuring the 4065A against the Tbolt? TBolt
> feeding the start and 4065A feeding the stop and a counter in time
> interval mode?
> On Fri, Nov 14, 2014 at 3:26 PM, Ed Palmer <ed_palmer at sasktel.net> wrote:
>> FYI, I found a source for the PLCC44 version of the STEL-1173 that's used in
>> some Datum FTS Cesium standards.  I got mine from here:
>> http://www.aliexpress.com/item/Free-shipping-10PCS-STEL-1173-CM-PLCC/2023682701.html
>> I left positive feedback, not sure why it doesn't show.
>> Shipping was very slow, but the chips appear to be NOS.  There are no
>> scratches on the leads which suggests that they were never installed in a
>> socket.  I was having trouble with one so I decided to sacrifice it to see
>> what was inside it.  The die is labelled 'ORBIT B-100'.  When I chopped out
>> the dead chip from my FTS-4065A, the bottom was stamped with the word ORBIT.
>> ORBIT Semiconductor works on FPGA to ASIC conversions.  It looks like
>> Stanford used Orbit as a fab house.
>> I'm currently measuring my 4065A against my Tbolt.  After about 37 hours,
>> I'm still not seeing anything that I can attribute to the 4065A. All I'm
>> seeing is the Tbolt and the typical response that every GPSDO gives.  I'm
>> looking at Total Deviation values of around 1E-13 at 100Kseconds.  Frequency
>> offset error appears to be about 6E-13.
>> All diagnostic status values are within spec.  I had to adjust the signal
>> level from the tube - it was too HIGH!
>> I decided to solder in a socket so that I won't have to go through any pain
>> if this chip dies in the future - and I now have spares!
>> Ed

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