Novus NR2306-O-G User manual

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 1
NR2306-O-G
10 MHz Six Channel Ultra Low Noise GNSS Locked
Frequency Reference
All information provided herein is the property of Novus Power Products LLC. The information
included may be reproduced without the permission of Novus Power Products LLC for the
purpose of operating the Novus equipment.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 2
Contents
1.0 Overview...................................................................................................................... 3
2.0 Controls and Indicators –Front Panel............................................................................... 6
2.1 GNSS Status....................................................................................................................... 7
2.2 GNSS Detailed Status.......................................................................................................... 7
2.3 Channel Status ................................................................................................................... 7
2.4 Status LEDs........................................................................................................................ 8
2.5 Alert Threshold................................................................................................................... 9
2.6 Latch Channel Values.........................................................................................................11
2.7 PPS Status ........................................................................................................................11
2.8 GPS Select (Dual Time Base Feature) .................................................................................13
2.9 Save Configuration ............................................................................................................14
2.10 Fault Status.....................................................................................................................14
2.11 UTC Mode .......................................................................................................................15
2.12 GMT Offset......................................................................................................................15
2.13 Power Switch...................................................................................................................16
3.0 Rear Panel .................................................................................................................. 16
3.1 Channel Outputs - BNC ......................................................................................................16
3.2 Antenna Input A/B - SMA ...................................................................................................16
3.3 DC Input...........................................................................................................................17
3.4 AC Input ...........................................................................................................................17
4.0 GNSS Receiver............................................................................................................. 17
5.0 Antenna...................................................................................................................... 19
6.0 Programming Guide (RS232 Port) .................................................................................. 20
6.1 RS232 / Status / Command ................................................................................................21
Specifications .................................................................................................................... 22
Performance .........................................................................................................................22
Environmental and Mechanical .............................................................................................22
LIMITED HARDWARE WARRANTY ....................................................................................... 23

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 3
1.0 Overview
The NR2306 is one of our most versatile and featured references. The
instrument starts with an ultra-low phase noise OCXO. The OCXO can be
locked to either the GNSS, an external PPS, external 10 MHz sine or an
external 1300nm fiber optic 10 MHz source.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 4
The typical phase noise is indicated below.
10 MHz Sine - Primary Output
Offset Frequency (Hz)
Typical (dBc / Hz)
1
-95
10
-140
100
-152
1000
-160
10000
-165
The disciplined OCXO drives a synthesizer to create a PPS from the OCXO to
dramatically reduce PPS jitter. PPS jitter directly from the GNSS receiver will
be as much as 5 to 10 ns of jitter introduced by the RF link - multi-path and
other effects. The internal control loop modulates the OCXO frequency to
maintain frequency and minimize the timing difference between the GNSS-PPS
and the synthesized PPS. The PPS output drive can be HVCMOS,LVCMOS or
50 Ohm compatible.
For even greater flexibility, the OCXO can be disciplined to an external PPS, 10
MHz RF or a fiber optic source. The fiber optic source is 1300nm single mode
or multi-mode.
The output amplifiers are safe area protected as well as transient and fault
protected. Each output is monitored with an RMS to DC converter. An alert can
be set-up to measure an over-voltage and under-voltage state.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 5
A front panel display, and pushbuttons allow the user to monitor and control the
instrument locally.
A RS232 port allows for local control and monitoring and an Ethernet port is
used for remote control and monitoring. The unit supports SNMP V04 for
remote access and control.
For GNSS locked configurations, a dual-time base option is offered. The
second time base effectively controls an embedded frequency counter to
confirm that the primary 10 MHz is within specification.
The unit consumes less than 10 watts of power and can operate from global
AC power: 90 to 240 Vac - 50/60 Hz.
The OCXO is a low phase noise device that is vibration-isolated from the PCB
assembly to attenuate mechanical vibration. In particular, 60 Hz fan vibration is
attenuated by ~ 20 db.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 6
Each output is monitored and transient and fault protected. Output amplitude is
measured and available via the RS232 port or optional Internet port. There is
also a status relay that is normally closed that will open if the unit fails self-test.
2.0 Controls and Indicators –Front Panel
This section describes the functionality of the front panel controls and indicators. Two
buttons above the status LEDs provide navigation through the menus.
In general, the NEXT button advances through the menus to the next screen, while the
SELECT button chooses between the available values on a menu.
Menus that allow selectable adjustments are the Input Threshold, Alert Threshold, and the
Attenuation setting. To adjust these values from the front panel, hold down both buttons for
two seconds, until the value begins to flash. To leave the menu with the new value, hold
down both buttons until the value is solid.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 7
2.1 GNSS Status
On power-up, the NR2306-O/G will display the Time and Date as well as the current status
of both GNSS receivers (if a dual-time base option was ordered).
GNSS: The GNSS status indication allows the user to observe the Lock status of the
receivers, and the number of GNSS satellites in view. Before GNSS lock is acquired, the
status will be “Tracking” and the number of satellites will be shown. When GNSS lock is
acquired, the status will change to “Lock.”
Time and Date: The time zone will be UTC by default, but the hour can be offset to the
local time in the UTC Offset menu. Changes to UTC offset and Hour mode will be reflected
on this screen, but will not change the NMEA output data.
2.2 GNSS Detailed Status
The GNSS Status Menu gives the user a quick reference for the quality of the GNSS
satellite signal and length of time that each receiver has been locked.
To toggle between each receiver, press the SELECT button. The screen will display which
receiver status is being viewed.
The user can then see the number of GPS satellites in view, number of GLONASS
satellites in view, and the UTC time and date that lock occurred on the selected receiver.
2.3 Channel Status
The Channel Status can be determined by reading the actual RMS value on the output of
each stage. This is compared to a threshold limit that is set by the user as a percentage
variation from a saved value. The default variation value is set at ±55% from the current
state of the amplifier and is user-programmable in 5% increments from ±10% to ±60%.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 8
The range of acceptable Channel Amplitude can be narrowed around a connected
balanced line, so that a Channel Status below the Alert Threshold indicates a shorted line,
while a Channel Status above the Alert Threshold window indicates a potential
disconnected cable.
The threshold value at which a channel alert is triggered can be programmed on the Alert
Threshold screen or programmed via the RS232 port. Once set, the unit would continue to
monitor each channel and a deviation beyond the set limits would be reported as a failure
on the front panel and via RS232.
The Channel Status feature can quickly detect a cabling failure. Any change in the load
impedance will change the output voltage with respect to the divider formed by the output
impedance of the amplifier and the load impedance. Failing cables and connectors can be
detected early.
The current threshold limits are displayed in addition to the actual measured value. These
values reflect the percentage threshold defined in the Alert Threshold settings. If the output
value is too low to give a valid reading, the display will read “LOW.”
The status is displayed on the front panel and is accessible over the RS232 serial bus via
DB9. Channel Statuses can be cycled into view or can remain on a single channel. This
feature can be accessed via the NEXT button by advancing to the Channel Status screen.
To cycle through channels in sequence, press the SELECT button.
Status information is also accessible through the SNMP capability.
2.4 Status LEDs
There are three status LEDs which provide a quick indication of valid unit operation.
Alert LED: The Alert LED will illuminate flashing RED to indicate A GNSS failure or a
power supply failure. The Alert LED will not flash RED if any valid input signal is present.
Oven LED (OCXO option only): The Oven LED will illuminate to indicate an oven failure.
Oven LED (on-board GPS): The Oven LED will illuminate steady GREEN if all on-board
GPS/GNSS units are locked. The LED will flash GREEN if at least one unit is unlocked.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 9
Fault LED: The Fault LED will illuminate flashing RED to indicate a channel fault, when
any single channel is outside the user-defined threshold.
2.5 Alert Threshold
The Alert Threshold screen allows the user to adjust the tolerance from the Reference
Voltage which, if exceeded in either direction, the output channels will report a fault status.
The default threshold value is set at ±55% percent from the current state of the amplifier,
and is user-programmable in 5% increments, from ±10% to ±60%.
Each channel has a Reference Voltage which can be set, all at once, by latching the
channels current value in the Latch Channel Average Screen. Each channels reference
voltage can be set individually by writing the value serially with the $SET command. After
saving the current configuration on a channel, any subsequent deviation on that channel
which exceeds the Alert Threshold percentage will trigger an alert.
Steps to ensure correct Alert configuration:
1. Connect distribution cabling to channels 1 through 6.
2. Set Alert Threshold to desired range.
3. Save current channel voltages with the Latch Channel Values Screen.
4. Save current settings on the Save Configuration screen.

USERS MANUAL
NR2306-O/G
REVISION
A
DATE
3-8-18
Page | 10
The Alert Threshold can be optimized so that a channel short or an impedance change will
cause an Alert.
Example:
The output of Channel 1 is connected to a high impedance input and reports 1.25Vrms at
the output. The output of Channel 2 is connected to a 50Ohm terminated input, and reports
0.90Vrms at the output.
Alert threshold is set to +/-20%.
The current state is saved in the Save Configuration screen.
The Channel 1 alert will report when:
-The Channel 1 output is higher than 1.50Vrms
-The Channel 1 output is lower than 1.00Vrms