Novus NR2310D-RO User manual

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
1
www.novuspower.com
NR2310D-RO
10 Channel, Low Noise, Rubidium Frequency Reference with
RS232, Display and optional Ethernet-SNMP
All information provided herein is the proprietary property of Novus Power Products
LLC. The information included may be reproduced without the permission or prior
approval of Novus Power Products LLC for the purpose of operating the equipment.

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
2
www.novuspower.com
Contents
Contents ...........................................................................................................................2
Safety................................................................................................................................3
Mounting ..........................................................................................................................4
Summary...........................................................................................................................5
The Time Base..............................................................................................................6
External PPS Locking ..................................................................................................8
The unit may be configured to lock to an external PPS signal. The signal must
conform to 3.3 V CMOS into a 1000 Ohm load. Rise time must be less than 10ns and
the pulse width must be greater than 10 ms.....................................................................8
PPS ...................................................................................................................................8
Base Unit Block Diagram...............................................................................................10
Phase Noise Performance...............................................................................................11
Controls and indicators...................................................................................................11
Channel Status- Front panel LED’s ...........................................................................12
Oven- LED front Panel...............................................................................................12
Digital Display (Optional)..........................................................................................12
RS232 NMEA / Alert –DB9 Male (Optional) .........................................................12
Rear Panel - Outputs.......................................................................................................13
Channel 1 through 10 output connectors –BNC or SMA .........................................14
Latch Channel Values ................................................................................................16
PPS –SMA (with GPS locking option) .....................................................................20
Alert –BNC-SMA......................................................................................................20
Power In......................................................................................................................20
Functional Description (Base NR2310D-RO) ...............................................................21
Outputs .......................................................................................................................21
Built-in Test....................................................................................................................21
Power Supplies...........................................................................................................21
Redundant power........................................................................................................22
Specifications .................................................................................................................23
Technical Specifications.............................................................................................23
Environmental and Mechanical..................................................................................24
Appendix C Novus Status and Control Strings..............................................................25
LIMITED HARDWARE WARRANTY .......................................................................26

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
3
www.novuspower.com
Safety
This product has been designed and manufactured to recognized safety standards and
rules. The product is a sophisticated electronic instrument that should be installed and
operated by highly trained professionals.
Installation of this equipment should comply with all local electrical codes.
Utilization of this equipment in a manner inconsistent with the operating instructions
can be dangerous.
There are no user serviceable parts within the unit. Removal of the cover to access
interior parts will expose the user to dangerous voltages.
The unit may be powered from more than one power source. Care must be taken to be
certain all power sources are removed before installation or during removal of the
equipment.
The unit must be operated with a secure earth ground to the chassis. The electrical path
for earth ground is through the power connector. The power switching device that
controls power to the equipment must never interrupt the chassis ground connection.
The equipment contains complex electronic components that can be damaged by
electrostatic discharge. Observe all recognize standards for the handling of complex
electronic devices to avoid high voltage discharge to the equipment. Be certain the
equipment chassis and operator are at equipotential before handling the equipment.

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
4
www.novuspower.com
Mounting
The equipment is meant to operate in a horizontal - top up configuration.
The equipment is meant to mounted into a 19 inch standard NEMA cabinet. The unit
occupies a single “1ru”. Mounting spaces above and below the equipment may be used
as required.
Please observe the operating temperature range for the equipment. If mounted into a
closed rack, be certain that the total heat load in the cabinet does result in an interior
operating temperature that exceeds the equipment maximum rated temperature.
If cooling must be used, care should be given to prevent cooling mechanical vibration
from the coupling into the equipment. Mechanical shock and vibration may introduce
noise into the electronic signals inside the equipment that may degrade the
performance of the equipment. For applications where there is significant shock and
vibration, Novus offers equipment with interior mechanical design features to
minimize the effects of vibration and shock on the equipment performance.

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
5
www.novuspower.com
Summary
The NR2310D-RO is a high performance 10 channel, 10 MHz, Rubidium frequency
reference. The core time base is a Rubidium source. The Rubidium source is followed
by a low noise OCXO locked to the Rubidium. The ten channels provide a 13 dBm
sine output that is transient, and fault protected. The unit also provides a single channel
simulated PPS output and a RS232 port. The RS232 port provides NMEA 0183 data as
well as proprietary data streams for instrument status and control. The unit features a
front panel display for equipment status and control. An optional ethernet port allows
remote access and control via SNMP. There are four levels of optional reference
control for improved Allan Deviation performance and PPS accuracy and jitter. The

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
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platform also supports redundant power sources AC or DC. The unit may optionally be
configured to lock to an external PPS signal.
The Time Base
The heart of the system is the reference. Novus offers OCXO and Rubidium
based references. Because of the relatively poor phase noise performance of
Rubidium, many of our customers select a Rubidium with a cleanup OCXO to
achieve high stability and low phase noise. Following is a plot of the phase
noise of a Rubidium reference and a Rubidium reference followed by a clean-
up OCXO.
Our Rubidium references offer a stability of < ±5E-11/month compared to a
typical OCXO ±50 ppb/year. The Rubidium source consists of a
voltagecontrolled crystal oscillator (VCXO) which is locked to a highly stable
atomic transition in the ground state of the 85Rb isotope.
Novus uses several vendors for the OCXO. The OCXO selected is based on
required phase noise, stability, and cost. There are other secondary
considerations such as size, power consumption, etc.

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
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In addition to standard OCXO devices, Novus also uses double oven OCXOs
as an alternative to a single oven OCXO. As can be imagined, a double oven
OCXO offers improved temperature stability and is frequently a lower cost
alternative to a Rubidium source.
A TCXO reference might be considered for a low-cost application. It offers an
aging stability that is on the order of ±1000 ppb/year. Phase noise is typically
not as good as that of an OCXO - but it is lower cost and consumes much less
power.
Stability/Year Temperature Adev@1 sec
ppb ppb/ 0 to 70C Seconds
TCXO <+-1000 <+-1000 1.00E-09
OCXO <+-50 <+-10 1.00E-10
Double OCXO <+-10 <+-0.2 5.00E-12
Rubidium <+-1 <+-0.1 5.00E-11
Timing Sources Comparison

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
8
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External PPS Locking
The unit may be configured to lock to an external PPS signal. The signal must
conform to 3.3 V CMOS into a 1000 Ohm load. Rise time must be less than
10ns and the pulse width must be greater than 10 ms.
PPS
The simulated PPS signal is available on a rear panel sma connector. There
are numerous attributes that can be controlled via the serial port or were
selected at the time the instrument was ordered.
Pulse Alignment (option)
Pulse Alignment Screen
Once the unit has achieved lock, and is in stable mode, the rising edge of the PPS can
be moved relative to the sine wave in 5ns increments. This allows for the PPS to align
to 20 positions in a complete cycle. To adjust the position of the PPS, allow the unit to
enter stable mode, and navigate to the Pulse Alignment screen with the NEXT button.
When unit reaches stable mode, the position of the PPS relative to the sine output will
be read from the reference module, and displayed as n/19, representing the positions 0-
19.
The position of the pulse, relative to the sine wave should be verified on an
oscilloscope during adjustment. The value on the screen does not necessarily indicate
fraction of cycle distance from rising edge. When adjusted, the pulse will advance 5ns
to the position of the sine output.
In order to increment the position of the PPS, press the SELECT button. The value of
the position, as read from the reference module, will increment. The read value will
indicate “Unlocked” until the unit has stabilized at the new set value.

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
9
www.novuspower.com
Wait 15 seconds before incrementing between steps. If the pulse moves excessively,
the unit may come out of stable mode. Simply wait for the unit to achieve stable mode
again before moving.
To save changes to non-volatile memory, go to “Save Configuration” screen, and press
SELECT.
Pulse Alignment over Serial Port
To set the PPS offset via the serial port, enter the value (0 to 19) with the $PSALN
command:
Example: $PSALN=2<cr><lf> Sets the PPS alignment to position 2 relative to
the sine.
To query the position of the PPS, enter $PSALN<cr><lf> with no parameters
following.
To save changes to non-volatile memory, enter “SAVEFLASH<cr><lf>”.

USERS GUIDE
NR2310D-RO
REVISION
C
DATE
042122
Page #:
10
www.novuspower.com
Base Unit Block Diagram
There is built-in test circuitry throughout the design. Power supplies, signal
present are monitored and are used to drive a status relay as well as indicators
on the front panel and optional serial and Internet communications paths.
The unit display allows local monitoring and remote monitoring via an RS232
serial link or ethernet port.
The ten-channel amplifier is designed for ultra-low noise to preserve the low
noise performance of the reference. This multi-channel design frequently
results in the elimination of a system distribution amplifier and consequently