[time-nuts] HP 5335a opt 40 addendum

Norman J McSweyn normn3ykf at stny.rr.com
Wed Oct 22 15:01:21 UTC 2008

Magnus Danielson wrote:
> Dear Norm,
> Norman J McSweyn wrote:
>> Magnus,
>> Thanks for the enlightenment!
>> I modified the driver that NI has on their site. Works. Have been 
>> manually setting the trigger levels on the front panel. Now know how to 
>> use the -40 to do it.
> Great! Happy to help!
>> I'll further modify the driver in the AM.
>> The manual I have doesn't have programming example 13.
> I haven't looked in detail, but I *think* the HP5335A manual on the HP 
> site is the same as I have, and then you should have all the details you 
> need.
Unfortunatly, the manual on Agilent's site is the one that I have, 
without the -40 addendum.
>> I take it that the instrument will trigger automatically when the 
>> conditions are met?
> Indeed it does.
>> I'm comparing the 1pps output from an M12+t to the divided down 10MHz 
>> out from a Thunderbolt.
>> Next hurdle is to do something with the collected data.
> Way to go!
> You should learn to calculate Allan deviation and friends. Not to hard.
> You should learn to estimate drift rate and subtract that from 
> measurements, since that is often ignored and the drift rate will form a 
> lower floor for longer measurement runs. This is an error which is 
> either canceled by locking or by software.
Data is time stamped and in a text file. One file is the TI data from 
the 5335a, the other is part of the @@Hn (with the sawtooth correction) 
message from the M12+T. In the interest of ensuring that I have a useful 
data set, I need to find a way to use Excel to check that no seconds 
have been skipped. Then post process the TI measurement to reflect the 
1pps sawtooth.

The next steps are a mystery. I drive locomotives for a living. This is 
  a hobby!! Have been playing with math for a while now, so it's not a 
black art! Didier has a few pages on measurements and one with tvb's 
explanation of Allan deviation. This will be today's reading!!!

Translating this into an Excel spreadsheet is the next hurdle.

Comparing the two devices (Thunderbolt to M12+T) is rather banal. It's 
like comparing two types of apples together. Not much difference. 
However, it's a steep learning curve to get to this point.

Any pointers are welcome!

Norm n3ykf
> Cheers,
> Magnus
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