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

Richard H McCorkle mccorkle at ptialaska.net
Mon Oct 31 16:56:09 EST 2005

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:

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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