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

Rex rexa at sonic.net
Sat Jan 15 05:10:41 EST 2005


Good to know your unit is working the same as I saw. 

If anyone gets one of these, bear in mind the 15 MHz multiplied output
is rather high level. If I remember correctly from my measurements it
would be around .25 W.

There are lots of unknown connections from the PLD chip to the 25-pin
connector.  Does anyone know if it is possible to distingush between an
input vs an output pin on a PLD chip? I was thinking maybe a curve
tracer might see a difference.

I would find it interesting to know what all those extra pins were for.

Even without the extra board, it is not a bad rubidium for the price.

-Rex

P.S., I have a Word doc on this unit that I would gladly pass on.  Some
here already have it, and one person duplicated my efforts in tracing
signals. Neither of us know what the extra pins are for.


On Fri, 14 Jan 2005 19:45:05 -0600, Brian Kirby <kirbybq at bellsouth.net>
wrote:

>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.
>
> 
>
>
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