Safran MR0 Series User manual

mRO Evaluation Kit User Manual Page 1of 16
Revision: 1 12 December 2023
ELECTRONICS & DEFENSE
MRO SERIES
Evaluation Kit Manual

mRO Series Evaluation Kit Manual, Rev 1
Page 2of 16
1. Introduction
The mRO-Series Evaluation Kit allows users to quickly interface an mR0-50 or mRO-50 Ruggedized
miniaturized Rubidium Oscillator. Through the RS232 serial interface, the user can communicate
with the mRO.
1.1. Designer Kit Serial
The mRO can connect to a PC via the RS232 port. During warmup time, which takes about 70
seconds, the mRO delivers data in calibration mode. The PC interrogates the mRO, which sends
back data, allowing for evaluation of the system.
2. Board Description
Evaluation board with mRO
A. Power supply with stabilized power unit +7Volts
B. Power selector: give the ability to supply the mRO with a stabilized power supply unit(A)
or from an USB PORT (C) coming from a personal computer
C. USB power to supply the mRO with a personal computer (USB voltage is around +5V)
D. Voltage frequency shift (from 0.5V min to 2.5V max) allows a +/- 8 ppb shift
E. Frequency adjust selector (Mechanical trimming (F) or external voltage frequency shift
input (D))
F. Mechanical frequency trimming allows a +/- 10 ppb shift
G. CMOS OUTPUT (0Vmin-5Vmax)
H. SINE WAVE OUTPUT (+5 dBm)
I. RS232 9600 Bauds
J. B.I.T.E OUTPUT (TTL logic)
K. B.I.T.E OUTPUT LIGHT: light off when lock
L. PPS IN (0V-5V): not used
M. PPS OUT (0V-3V not loaded): not used
N. POWER SUPPLY LIGHT

mRO Series Evaluation Kit Manual, Rev 1
Page 3of 16
3. Operating & Hardware System Requirements
The following supplies are required:
1. Microsoft Windows operating systems requirements:
•Windows 10-64 Bits or Windows 11-64 Bits
•Screen Resolution: at least 1680x1050
•A free serial port (RS232, 9 pin Sub-D)
2. A 7V/0.5A properly filtered power supply, and a power cable with two wires of different
colors.
3. USB socket coming from the PC is strong enough to supply the mRO even during warmup
time if there is no power supply available.
4. A serial cable with 9 pin Sub-D connectors. One connector male, the other female.
•Pin 2 connected to pin 2.
•Pin 3 connected to pin 3.
•Pin 5 connected to pin 5.
5. A frequency counter with an external reference input.
4. Installation Procedure
4.1. Safety
Warning: Use proper ESD precautions.
Warning: Ensure that all cables are properly connected.
The equipment contains small quantities of rubidium metal hermetically sealed inside the glass
lamp and cell assemblies, hence, any dangers arising from ionizing radiation are caused for human
health (exemption set in article 3 to Council directive 96/29/Euratom).
Handling the product in reasonably foreseeable conditions does not cause any risk for human
health, exposure to the SVHC (substances of very high concern) would require grinding the
component up.
4.2. Environmental Responsibility
The equipment contains materials, which can be either re-used or recycled.
Do not deposit the equipment as unsorted municipal waste. Leave it at an authorized local WEEE
collection point or return to Safran to ensure proper disposal. In case of disposal by Safran, the
costs related to return freight will be charged to the sender.
To return the appliance:
Submit a support ticket at https://safran-navigation-timing.com/support-hub/
We will contact you for more information and/or with shipment process details.

mRO Series Evaluation Kit Manual, Rev 1
Page 4of 16
5. Safran mRO application control software
5.1. Setup
Start the executable SpectraMon v3.0.0.exe (can take up to 20s to execute) and open the Settings
window.
Settings window
Select the available COM port connected to the evaluation board and press Connect:
Connect button
The software will automatically detect the type of mRO (mRO-50 or mRO-50 Ruggedized). The
type of the mRO and the serial number will be display at the left of Connection button.
mRO detection type

mRO Series Evaluation Kit Manual, Rev 1
Page 5of 16
To record data coming from the mRO, select the filename path, and check the Record box.
Data record
All data parameters coming from the mRO can be recorded inside a dedicated “record file”
according to the timegate. The software records 27 parameters:
1. Unix_Timestamp: System (PC) time in seconds
2. IPhot(int): Photodiode data measured by the mRO, this is an int value
3. Atomic_SIGNAL_MIDDLE_RANGE (int) Satom 15: signal level data on the first side of the
Rubidium line
4. Atomic_SIGNAL_UPPER_RANGE (int) Satom 31: signal level data on the second side of the
Rubidium line
5. Heating_Power_Laser (int): heating power dissipated in order to warm the laser diode
6. Heating_Power_Rb_cell (int): heating power dissipated in order to warm the Rb cell.
7. Laser_source (int): voltage supply of the unit powering the laser diode of the mRO
8. Laser_Voltage (int): laser voltage, measured by the mRO
9. MiniRb_Temperature (int): temperature signal of the mRO
10. Voltage_control_TCXO (int): DAC value connected to the 10 MHz TCXO voltage control
input
11. CFIELD (micro-Amp): current flowing through the magnetic coil in micro-Amp
12. Temperature cell setting (int): temperature setting point of the Rb Cell
13. Temperature laser setting (int): temperature setting point of the laser
14. Pil Laser (int): polarization of the power amplifier which drive the laser
15. PIL_CFIELD (int): polarization of the power stage which drive the current flowing through
the magnetic coil
16. PIL Polar AOP (int): pre-polarization of the power stage which drive the laser
17. PIL VC: TCXO voltage control input
18. Status: mRO status
19. Rb_cell_temperature_setting point (°C): temperature of the rubidium cell
20. Laser_temperature_setting point (°C): temperature of the laser
21. MiniRb_Temperature (°C): temperature of the mRO
22. Laser_current (micro-Amp): current flowing through the laser diode.
23. Photodiode current (nano-Amp): current flowing through the photodiode.
24. Heating_Power_Rb_cell (mWatt): heating power dissipated to warm the Rubidium cell
25. Heating_Power_Laser (mWatt): heating power dissipated in order to warm the Laser
26. Cell heating current (mA): Current in milliAmp flowing through the heating system of the
Rb cell
27. Laser heating current (mA): Current in milliAmp flowing through the laser heating system.

mRO Series Evaluation Kit Manual, Rev 1
Page 6of 16
The Power supply of the mRO can be selected, it gives the ability to the software to compute the
right power dissipated by the Rb-cell heating system and laser heating system.
Power supply selection
The mRO will be contacted according to the Timegate parameter (configured in seconds).
Timegate selection
The mRO memory can be recorded inside a dedicated “mRO parameters” file. Select Save to record
these parameters.
Memory record
When the software is executed, an ApplicationControlSettings.ini file is created in the same path
as the executable. This file saves the settings in the Settings window, so that when you restart the
software, the settings configured will be the last settings used.

mRO Series Evaluation Kit Manual, Rev 1
Page 7of 16
5.2. Safran mRO series application control monitor
To begin monitoring the mRO, open the Monitor window and select Start Measurement.
Monitor window
When the start button has been selected, data monitoring will plot to a graph in the Measure
window.
Measurement ON
At the bottom left monitor box, the status of the commands sent to the mRO appears.
On the bottom right monitor box, items received by the mRO in HEX appear.
The content of both windows can be cleared by pressing Clear Data on the right side.

mRO Series Evaluation Kit Manual, Rev 1
Page 8of 16
There is a moving graph on the right of the main window, with a sliding time window equals to 3
minutes (180 seconds).
The Window size can be set between 10 and 600 seconds.
Window size
On this graph, nine parameters are presented. All presented data are in a range going from 0 to
4095.
-MON Satom15 and MON Satom31 are samplings taken from the output of the photodiode
amplifier used to center the mRO on the Rb line. Both values must be in the same range.
-MON IPHOT is the signal level output coming from the photodiode.
-MON HLASER is the heating system’s level output, which drives the laser diode
temperature.
-MON HCELL is the heating system’s level output, which drives the Rubidium Cell
temperature.
-MON Laser VPIL is the power stage level output, which drives the laser diode.
-MON Laser PIL is the laser diode voltage.
-MON TPCB is the temperature of mRO.
-PIL DAC VCfor the mRO-50 is the 10 MHz TCXO voltage control input, which drives the
atomic clock.
-PIL DAC VC/16 for the mRO-50 Ruggedized is the 10 MHz TCXO voltage control input,
which drives the atomic clock. It is divided by 16 for correct display in the graph.
All parameters presented on the graph can be toggled on and off by clicking on the corresponding
parameter label at the bottom of the graph pane, that the user needs to visualize or hide
respectively.
5.2.1. Cell temperature window
This window shows 5 parameters:
1. Temperature: the setting point temperature of the Rubidium cell
2. Pil HCell: the hexadecimal value of Temperature
3. Photodiode: the current flowing through the Photodiode, which collects light going
through the Rubidium cell.
4. Heating Current: the current used by the heating system in order to warm the Rubidium
cell.
5. Heating Power: the total power dedicated to warm the Rubidium cell.
Cell temperature window

mRO Series Evaluation Kit Manual, Rev 1
Page 9of 16
5.2.2. VCSEL temperature window
This box shows 5 parameters:
1. Temperature: the setting point temperature of the laser diode
2. Pil HLaser: the hexadecimal value of Temperature
3. Current: the current flowing through the laser diode, which emits the light going to the
Rubidium cell.
4. Heating current: the heating used by the heating system in order to warm the laser diode.
5. Heating Power: the total power dedicated to warm the laser diode.
6. Servo loop: the Padlock shows the state of the laser loop.
VCSEL temperature window
5.2.3. Laser lock control window
This box shows the settings of the power amplifier, which is driving the laser diode. The padlock
shows the state of the laser loop.
Laser lock control window
5.2.4. Atom lock control window
This box shows the status of the digital loop, which drives the VCTCXO 10MHz.
Atom lock control window

mRO Series Evaluation Kit Manual, Rev 1
Page 10 of 16
5.2.5. Coarse frequency window
This window shows the Modulator value of the digital PLL which drives the signal used in order to
set the mRO output frequency according to the Rb line.
Coarse frequency box
5.2.6. CField window
The mrO-50 CField window shows 4 parameters:
1. CField is the relative offset value used for the fine frequency adjustment.
2. Pil CField is the setting value of the power stage, which drives the current flowing through
the magnetic coil.
3. Current is the current value of the magnetic coil.
4. Servo loop is the status of the CField loop
CField box window mRO-50
The mRO-50 Ruggedized CField window shows 3 parameters:
1. CField is the relative offset value used for the fine frequency adjustment.
2. Pil CField is the setting value of the power stage, which drives the current flowing through
the magnetic coil.
3. Current is the current value of the magnetic coil.
CField window for mRO-50 Ruggedized

mRO Series Evaluation Kit Manual, Rev 1
Page 11 of 16
5.3. Frequency setting
Open the Calibrate window and navigate to the Frequency settings tab.
Frequency settings tab
5.3.1. Command window
The Command window gives the ability to the mRO to lock automatically on the Rb line after power
ON.
Command window
5.3.2. Cell temperature window
The Cell temperature window set the temperature of the Rb cell is set.
Cell temperature window
The higher is the temperature of the Rb cell, the lower is the photodiode current.
Apply: applies the value of the temperature box to the RAM of the microprocessor of the mRO.

mRO Series Evaluation Kit Manual, Rev 1
Page 12 of 16
Save: saves the value of the RAM inside the ROM of the microprocessor.
5.3.3. Coarse frequency window
This window allows the user to change the mRO frequency by 1.24 ppb step.
Coarse frequency window
Warning:It is highly recommended to set the frequency adjust selector of the evaluation board on
FA and to let the SMA connector (D) free of any coaxial cable when the coarse and fine frequency
setting are used.
The + and – buttons increase or decrease the modulator value, and act immediately on the
frequency output of the mRO.
The Modulator value can be written and the Apply button can be pressed to apply the new
Modulator value. It is highly recommended to not exceed +/- 500 steps relative to the original
default value.
Wait at least 6 seconds after each new modification, as the mRO system needs time to change the
frequency output due to the high-quality factor of the atomic loop.
The PLL modulator can set the mRO frequency output in a range of 9 999 995.00 to 10 000 005.00
Hz (+/- 500 ppb) without any stability degradation.
Select the PLL Savebutton to save the Modulator value inside the ROM of the microprocessor.
5.3.4. CField window
This window allows the user to modify the mRO frequency by about 2.5 ppt step. (0.0025 ppb).
The CField value represents the current flowing through the magnetic coil.
CField window
Warning: It is highly recommended to set the frequency adjust selector of the evaluation board on
FA and to let the SMA connector (D) free of any coaxial cable when the coarse and fine frequency
setting are used.
The + and – buttons increase or decrease the CField value, and also affect the frequency output of
the mRO.
The CField value can be written and the Apply button can be pressed to apply the new CField
value. When the frequency output is set in the appropriate range, the Save button is activated.
It is highly recommended to not exceed +/- 500 steps relative to the original default value.

mRO Series Evaluation Kit Manual, Rev 1
Page 13 of 16
5.3.5. Servo loop window
This box allows the user to open the 4 mains digitals loops of the mRO.
Servo loop window for mRO-50 (left) and mRO-50 Ruggedized (right)
The Vcsel compensation loop can be opened without any condition, 10 minutes after power ON.
The Thermal compensation and PILPOLARAOP Thermal compensation loop can be opened
without any condition, 10 minutes after Power ON. The Atom loop can be opened without any
condition, 10 minutes after power ON. It is not recommended to open the Laser loop.
The Refresh button requests the status of the 4 mains digitals loops from the mRO.
5.4. Update of the mRO firmware
It is possible to erase and load a new firmware without erasing the data relative to the operating
mode of the mRO.
To do that open the Firmware update window and select the path to the new firmware.
Firmware update window

mRO Series Evaluation Kit Manual, Rev 1
Page 14 of 16
Select a path in order to save all parameters of the mRO and press Start.
Firmware update window
Firmware update ongoing, firmware is written inside the microprocessor.
It takes around 4 minutes maximum to update the mRO to new firmware.
Firmware update window

mRO Series Evaluation Kit Manual, Rev 1
Page 15 of 16
After that update is done, the mRO restarts automatically.
Firmware update window
6. Safran Technical Support
For technical support, product specifications, and additional documentation, you can visit
https://safran-navigation-timing.com/support-hub/mro-50-support-hub/ to submit a support
request.
More information on standard unit behavior or any other features or functions of the mRO series
can be found on our website at https://safran-navigation-timing.com/product/mro-50/

mRO Series Evaluation Kit Manual, Rev 1
Page 16 of 16
Information furnished by Safran is believed to be accurate and reliable. However, no responsibility is assumed
by Safran for its use, nor for any infringements of patents or other rights of third parties that may result from
its use. Safran reserves the right to make changes without further notice to any products herein. Safran makes
no warranty, representation or guarantee regarding the suitability of its products for any particular purpose,
nor does Safran assume any liability arising out of the application or use of any product or circuit, and
specifically disclaims any and all liability, including without limitation consequential or incidental damages. No
license is granted by implication or otherwise under any patent or patent rights of Safran. Trademarks and
registered trademarks are the property of their respective owners. Safran products are not intended for any
application in which the failure of the Safran product could create a situation where personal injury or death
may occur. Should Buyer purchase or use Safran products for any such unintended or unauthorized
application, Buyer shall indemnify and hold Safran and its officers, employees, subsidiaries, affiliates, and
distributors harmless against all claims, costs, damages, and expenses, and reasonable legal fees arising out
of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized
use, even if such claim alleges that Safran was negligent regarding the design or manufacture of the part.
Safran Electronics & Defense safran-navigation-timing.com