[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