[time-nuts] Ebay FE-5680A Rb: Are they that good?

Bob Smither smither at c-c-i.com
Sat Dec 10 02:51:07 UTC 2011


Bob Smither wrote:

<snip>

> My documentation states that the full range of adjustment is:
> 
>   7f ff ff ff => +383 Hz
>   80 00 00 00 => -383 Hz

This scale factor is clearly wrong - using it and applying an appropriate 
correction changes the frequency way too much.

From:

   http://article.gmane.org/gmane.comp.time.nuts/9473/match=fe+5680+pin+outs

(thanks Jose!) a better estimate is 140000 / Hz.

Using data after 20 hours:

   http://www.c-c-i.com/node/155

the estimated frequency offset is 1.36E-3 Hz.  Using the above scale factor 
gives a correction of -190 counts.  Here is the command I used to (temporarily) 
program the new offset:

   2e 09 00 27 ff ff ff 42 bd

(the bd is the exclusive-or checksum of the offset)

Now I wait ...
-- 
Bob Smither, PhD                                   Circuit Concepts, Inc.
=========================================================================
    A government which robs Peter to pay Paul can always depend on the
    support of Paul.
    --George Bernard Shaw
=========================================================================
Smither at C-C-I.Com  http://www.C-C-I.Com  281-331-2744(office)  -4616(fax)
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