[time-nuts] Equipment question: OCXO versus GPSDO + XTAL

Wolfgang Wieser timenuts at triplespark.net
Sat Mar 19 02:18:21 UTC 2011


Hello all,

first, thanks for all the answers!

Maybe let me ask the more fundamental question: Completely independent 
of use scenarios and so on: Assume device A uses standard reference tied 
to ultra-stable zero-drift magic 10 MHz refclock. Device B uses TXCO option. 

Is there any measurement type with any strange setup that you could imagine 
where B outperforms A just because the combo "standard XO + refclock" 
is inferior in any respect compared to "TXCO". (Lab/shop equipment, 
no portability needed.)

I mean - not necessarily for this particular Agilent 53230A but for anything 
of this type and class. 

@Bill: 
thanks - exactly the type of advice/opinion I was hoping to get. 

@Paul Swed: 
> Unfortunately in the first round of the thread you did not say what you are
> actually doing with the system and whats important to you.
Measuring time and frequency? Maybe there are some unknown issues that I am 
not aware of but what I would like to know is whether for any usual 
measurement made with a timer/freq counter the choice of XO+refclock could 
be inferior to TXCO. If there are significantly different scenarios in 
your mind - it would be nice to let me know for what type of measurement 
you think that the one is better and for what not. 
Anything except portability issues?

> The last answers actually the best considering the base system initial
> investment. 
Well, once a year I buy something more expensive...
However, while 2500 EUR seems reasonable for the counter, additional 
1000 EUR seems a bit much for the OCXO option. 

@Joe
> You will have to look at the stability measurements of the OCXO versus the
> GPSDO to choose that one.
OK, do you have an educated guess about the outcome of that?
Because acutally doing this comparison exceeds my scope ATM. 

@Greg
> My opinion is that first you need to tell more about how you
> are going to use this counter. For work in the shop where
> a distributed reference is always available (...)
>
Hm.. OK.. I re-formulated into the question on the top. 

> I am suspicious of the note that this OCXO upgrade can only
> be done at the factory.  See if you can get the control sequence
> to cause reference autocal.
I've got a test unit ATM and there actually is a security code to 
unlock the calibration. I don't know the code right now. 

- Wolfgang, DL1SKY



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