[time-nuts] Ebay's testeqe's rubidium board

Brian Kirby kirbybq at bellsouth.net
Sat Jan 15 01:45:05 UTC 2005


Rex recently shared some information on the rubidium and the board that 
"testeqe" is selling on Ebay.  I used the rubidium by itself in its own 
project and had the board left over.

At first, I thought the board was bad - I did not see a 15 MHz output.  
But after reading Rex's info, you have to wait on the board to come up, 
it has a timer.  I found in my case the board had output at 2 min's and 
15 seconds.  All info was as Rex described it.

Also, the board by itself draws 230 ma from the 24 volt source (without 
the rubidium connected to it).  I set the board up stand alone by 
jumpering J5 pin 4 to ground (lock) and feeding a 10 MHz TTL signal to 
J5 pin 10.

The Altera EP610PC-25T chip has the 10 MHz going in at pins 1 and 13, 
and a TTL 5 MHz out on pin 5.

The CD4060 chip does not appear to be synchronized to the system.  Pin 
11 has a 62.7 hz triangle waveform, Pins 10, 9 have a TTL 62.7 hz 
signal.  Pin 4 - 1 hz,  pin 5 - 2 hz, Pin 6 - one pulse per 2 seconds, 
Pin 7 is 4 hertz.

On the 74HC4538, Pin 2 has a 3.750 MHz ramp with a +0.5 dc offset.  Pin 
4 is 15 MHz and pin 12 is 15 MHz.

In my case, I hate to threw out a useful synthesizer, so I am mounting 
it in a case with BNC connectors.  I plan to use the 15 MHz output   
(J2) as is.  I am taking a 10 MHz feed from J3, buffering it via 74AC04s 
as a output.  Below the Altera chip is a 5 pin header/test points 
labeled J1TP.  Pin 2 has a 5 MHz TTL signal.  I am also buffering it 
out, as a output.

 





More information about the Time-nuts_lists.febo.com mailing list