[time-nuts] Unknown Efratom 10MHz Assy, information asked

Arnold Tibus Arnold.Tibus at gmx.de
Mon Oct 31 18:20:52 EST 2005

Hello Richard,
if it helps? Y e s , thank you very much! 
I found everything as you describe. 
I know now what I thought already, that the supply is 24Vdc, the pins I had 
allocated already. 
What I did not know is that the task is to generate 15 MHz using a 10 MHz OCXO. 

Underneath the top board I found the 15 MHz crystal filter. 

I will start to investigate more and perform some measurements. 
Perhaps there will be somebody able to add some more details.

A pity that I do not see anymore the possibility to use the board with GPS.

Many thanks Richard again for you detailed mail,


On Mon, 31 Oct 2005 12:56:09 -0900, Richard H McCorkle wrote:

>The board you are describing is used in the Lucent RFG-M-XO reference
>frequency generator. It takes in 10 MHz on J2 from a Rubidium oscillator and
>disciplines the Efratom SC cut OCXO on the main board from the 10 MHz input.
>The output from the OCXO is converted to 15 MHz and supplied as the
>reference output on J4.
>The RFG-M-RB and RFG-M-XO normally mount together in a chassis (which I didn
>'t get) and the modules are connected to the chassis by a harness with a
>DB15 on the chassis end. The pin out for the harness is as follows:

>DB15M     TO/Pin#                  Description
>Pin #
>1            RFG0 - P1-1            +24v 1.3A/0.6A
>2            RFG0 - P1-2            Common
>3            RFG1 - P1-1            +24v 0.6A/0.4A
>4            RFG1 - P1-2            Common
>10          RFG0 - J3-1             Alarm
>11          RFG0 - J3-2             Alarm
>12          RFG1 - J3-1             Alarm
>13          RFG1 - J3-2             Alarm

>A second interface cable ties the RB to the XO as follows:

>RBJ5   XOJ5
>Pin #    Pin#
>1            5
>3            3

>The male DB9 is P1 and pin 1 = +24v @ 400ma, Pin 2 = Common. This will power
>up the board so you can verify operation of the OCXO. Unfortunately that is
>all the information I have on the unit.
>Hope this helps.

>----- Original Message ----- 
>From: "Arnold Tibus" <Arnold.Tibus at gmx.de>
>To: "Discussion of precise time and frequency measurement"
><time-nuts at febo.com>
>Sent: Monday, October 31, 2005 10:02 AM
>Subject: [time-nuts] Unknown Efratom 10MHz Assy, information asked

>> Hello to the group,
>> I have got in my hands a very nice looking board
>> from EFRATOM equipped with a 10 MHz OCXO.
>> The designation on the top of the board is
>> 55761ASSY104920-001
>> the label underneath shows
>> 55761-104919-001
>> The Ocxo P/N is 105243-001, 10,00MHz
>> The board is complete with 3 x 9pin D-Type connectors
>> 2x fem. 1x male, which seem to be the connector
>> for the powering of the assy.
>> There are 2x SMA conns. fem., J2 and J3, J1 is not
>> assembled.
>> For memory backup there is a mignon battery holder on.
>> The small board monted on top of the main board
>> does have a PLL system with a 74HC4046N and a lot
>> of other typical chips assembled (CD4060, 74HC08,
>> 54HC573F, AD75388Q and others.).
>> I guess this was a part of a Rb-reference device,
>> too nice to disassemble.
>> Therefore I ask into the round table all the experts, if there
>> is somebody who could help me with more details, circuit diagram
>> or I/F informations etc.
>> As I am anyway trying to set up a GPS disciplining system
>> for a 10 MHz OCXO or a Rb LPRO oscillator.
>> BTW. I am enjoying since a few weeks following all the expert
>> discussions on this site and I red most of the technical issues
>> a few years backwords, I learned a lot, thank you all the
>> excellent discussions and informations of the experts.
>> I would be happy to get informative answers and help,
>> thanks in advance,
>> excuse me my struggling english please, I am willing to learn as
>> well on that point.
>> Arnold, DK2WT
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