[time-nuts] any HP 5370B Available or other TIC

EWKehren at aol.com EWKehren at aol.com
Fri Aug 19 12:57:42 UTC 2011


Paul, 
following all the responses to this posting I think a old fashioned D/M is  
still the answer for you. For years there have been discussions on using 
latest  technology but limited to discussion no hardware. Maybe now is the 
time it will  change. 
 That is why two years ago I set out do develop a D/M system based on  the 
original NBS design but with its own counter and a cost goal of $ 200 and  
readily available parts.. Thanks to Richard, Corby and Hubert there are now  
eight systems out there with very good results. Cost goal was reached if 20 
PC  board sets are purchased. The actual D/M right from NBS, more densely 
packaged  for better temp. tracking and later components. Corby's tests show a 
noise floor  of 1 E-13. Resolution is 1 E -15. I did post in the past a 
picture but it is  115K, so off list I can send more info.
What is holding up the release is software that takes the counter  outputs  
and does the Allan deviation calculations and plots.
What is not included in the $200 is the offset Osc,, power supply and  
outside enclosure. Depending on the OCXO used it will drive the total cost to  
$300 even $ 400 if 10 Hz is used. But no counter needs to be used.
If you use a 1 Hz offset many choices for OCXO are available I have used an 
 Austron 1150 and more recently thanks to a lead from Hubert a Morion that  
is available on ebay for $40. He characterized it with the D/M system.
If you want to use 10 Hz offset the only choice I know is the HP 10811. All 
 the ones I have can be mechanically moved at least + - 20 Hz.
I know nothing about the Keithly 776 so I do not know if it will work. You  
may want to contact me off list.
The attached drawing of the counter (thank you Brian Kirby) gives you an  
idea of my counter approach. It is $ 30 of the $ 200. Tipically the phase  
between channel A and B are measured, but that creates times depending of 
phase  when the counter can not keep up because it needs time for processing and 
 transfer of data. My concept does also have such a counter but it is only 
used  to position phase or once a run is completed to pick a section where 
channel A  and B are in phase to eliminate any contribution by the offset 
oscillator. Two  counters each per channel count the 1 or 10 Hz frequency at 
100 MHz, resulting  at 1 Hz with 1 E-15 and at 10 Hz 1 E-14 way better than 
the D/M noise floor. The  counters work in a ping pong mode so there is 
continuous counting, I call it  pseudo time stamping. It also allows you to "tune" 
the unknown close to the  reference at a 1 or 10 Hz rate. These  four 
counters are used for the Allan  calculations.
This unit never needs a counter, once you connect Reference and PC you can  
tune the offset exactly to 1 or 10 Hz, connect the unknown, "tune" it and 
you  are ready to go. PC interface is RS 232 or USB.
What is needed is some one tackling the PC software issue.
 I will not get into the kit business. At one time I was considering  to 
coordinate a one time PCB run and even make some HP 10811's available since  
thanks to Corby's testing, I have ten 10811  and 5071 HP OCXO's with better  
than 1 E-12 over 1 to 100 sec..range, but after Jose Camara's comment that 
is no  longer an option for me. I will once a final board set has run with  
software make all info available, and hopefully some one will pick it up.  
The reason I am right now reluctant to release the PCB board code is if 
changes  need to be done it will be impossible to get rid of the previous code.
If any one wants go get involved software or hardware wise please contact  
me off list.
  
Bert Kehren
 
 
 
In a message dated 8/17/2011 11:11:30 P.M. Eastern Daylight Time,  
paulc at snet.net writes:

Hello  Folks,
I am looking for an instrument that is better than Fluke 103a  comparator.
The purpose of this piece of equipment is help me learn more  about 
oscillators and characterizing them

The HP5370B is the TIC  I keep hearing about but I am not glued to that 
make or model.
I wou;d like  to hear suggestion from the group.

Another way to go might be to  build one of those units where there is a 
common oscillator is split  and feeds the LO of 2 mixers.
The RF side comes from the DUT and the  REF  
Sorry I cannot remember the  acronym... MDMM????

I do have that Keithly model 776 Counter  time with GPIB  I am really fuzzy 
on this aspect...

Comments  welcome 

Thank  you

PaulC
W1VLF



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