Difference between revisions of "OctoClock CDA-2990"

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== Device Overview ==
 
== Device Overview ==
−
The OctoClock is an affordable solution for high-accuracy time and frequency reference distribution.  The OctoClock accepts 10 MHz and PPS signals from an external source, and distributed each signal 8 ways.  This is a useful accessory for users that would like to build multi-channel systems that are synchronized  to a common timing source.  
+
 
 +
The OctoClock CDA-2990 is an affordable solution for high-accuracy time and frequency reference distribution.  The OctoClock accepts 10 MHz and PPS signals from an external source, and distributed each signal 8 ways.  The OctoClock is a useful accessory for users that would like to build multi-channel systems that are synchronized  to a common timing source.
 +
 
 +
The OctoClock-G CDA-2990 provides the same functionality as the OctoClock CDA-2990, but includes a GPSDO that can be used to produce internal 10 MHz and PPS signals, as well as a front-panel switch to select between internal and external sources for the signals. Note that ''both'' signals must come from the same chosen source: either ''both'' are generated internally from the GPSDO, or ''both'' are provided from the external inputs.
 +
 
 +
'''Note:''' Both of the CDA-2990 devices are functionally identical to the previous generation OctoClock, which contained an Ettus Research logo.
  
 
== Key Features==
 
== Key Features==
Line 10: Line 15:
 
*External 10 MHz/1 PPS Source Required
 
*External 10 MHz/1 PPS Source Required
 
*19" Rackmount – 1U
 
*19" Rackmount – 1U
−
|[[File:Product octoclock.jpg|250px|center]]  
+
|[[File:Product octoclock.jpg|450px|center]]  
 +
|[[File:octoclock2.png|450px|center]]
 +
 
 
|}
 
|}
  
 
==Signal Levels==
 
==Signal Levels==
−
; 10 MHz output : 1.25 Vpp at 50 ohms, 3.3Vpp at 1M ohms
+
{|
 +
|style="vertical-align:top"|
 +
; 10 MHz output : square wave with close to 50% duty cycle; 1.25 Vpp at 50 ohms, 3.3Vpp at 1M ohms
 
; 1 PPS output: 20% duty cycle square wave with amplitude 5 V
 
; 1 PPS output: 20% duty cycle square wave with amplitude 5 V
  
 
; 10 MHz input : 0-20 dBm
 
; 10 MHz input : 0-20 dBm
 
; 1 PPS input: 2.5-5 V
 
; 1 PPS input: 2.5-5 V
 +
|[[File:octoclock1.png|450px|center]]
 +
|[[File:octoclock3.png|450px|center]]
 +
 +
|}
  
 
==Physical Specifications==
 
==Physical Specifications==
 
===Dimension (1U Rackmount)===
 
===Dimension (1U Rackmount)===
 
4 x 17.187x 1.75 inches
 
4 x 17.187x 1.75 inches
 +
 +
===Weight===
 +
2.6 lbs
 +
 +
===Drawings===
 +
* [[File:cu ettus octoclock cca.pdf]]
 +
* [[File:cu ettus-octoclock.pdf]]
 +
 +
===CAD/STP Models===
 +
====OctoClock CDA-2990====
 +
* [[Media:cu ettus octoclock cca.stp.gz| Motherboard]]
 +
 +
====OctoClock CDA-2990====
 +
* [[Media:cu ettus octoclock.stp.gz|Enclosure]]
  
 
==Environmental Specifications==
 
==Environmental Specifications==
Line 30: Line 57:
 
===Operating Humidity Range===
 
===Operating Humidity Range===
 
* 10% to 90% non-condensing
 
* 10% to 90% non-condensing
 +
 +
==Input/Output Impedance==
 +
All RF Ports are matched to 50 Ohm with -10dB or better return loss generally. Detailed test is pending.
 +
 +
==Ethernet Port==
 +
The Ethernet port on the OctoClock and OctoClock-G allows the device to be connected to the network. When connected, the <code>uhd_find_devices</code> utility can find any OctoClock devices on the network, and the device's firmware may be updated over Ethernet using the <code>octoclock_burn_eeprom</code> utility. In addition, with the OctoClock-G, NMEA strings may be obtained from the internal GPSDO via the UHD API. Note that there is no host CPU in the OctoClock, so it is not possible to SSH into the device.
  
 
==Schematics==
 
==Schematics==
Line 41: Line 74:
 
!Schematic ID (Page)
 
!Schematic ID (Page)
 
|-
 
|-
−
|[http://ww1.microchip.com/downloads/en/DeviceDoc/39662e.pdf ENC28J60−DIG]
+
|[https://ww1.microchip.com/downloads/en/DeviceDoc/39662e.pdf ENC28J60−DIG]
 
|Ethernet Controller
 
|Ethernet Controller
 
|U103 (1)
 
|U103 (1)
 
|-
 
|-
  
−
|[http://www.atmel.com/images/doc2467.pdf ATmega128]
+
|[https://ww1.microchip.com/downloads/en/DeviceDoc/doc2467.pdf ATmega128]
 
|Microcontroller
 
|Microcontroller
 
|U102 (1)
 
|U102 (1)
 
|-
 
|-
  
−
|[http://www.mymectronic.com/datasheet/13059_4168782_m9107.pdf M9107]
+
|[https://www.jackson-labs.com/index.php/products/lc_xo LC_XO] [https://www.jackson-labs.com/assets/uploads/main/LC_XO_specsheet.pdf Spec Sheet] [https://www.jackson-labs.com/assets/uploads/main/LC_XO_Manual.pdf Manual]
−
|SMT OCXO-Based GPSDO
+
|Jackson Labs LC_XO (OCXO)
 
|U206 (2)
 
|U206 (2)
 
|-
 
|-
  
−
|[http://www.ti.com.cn/cn/lit/ds/symlink/sn74aup1t57.pdf SN74AUP1T57]
+
|[https://www.ti.com.cn/cn/lit/ds/symlink/sn74aup1t57.pdf SN74AUP1T57]
 
|VOLTAGE-LEVEL TRANSLATOR
 
|VOLTAGE-LEVEL TRANSLATOR
 
|U204, U203 (2)
 
|U204, U203 (2)
 
|-
 
|-
  
−
|[http://www.ti.com/lit/ds/symlink/cdce18005.pdf CDCE18005−PWR]
+
|[https://www.ti.com/lit/ds/symlink/cdce18005.pdf CDCE18005−PWR]
 
|Output Clock Programmable Buffer
 
|Output Clock Programmable Buffer
 
|U205 (2)
 
|U205 (2)
 
|-
 
|-
  
−
|[http://www.nxp.com/documents/data_sheet/74HC_HCT4020.pdf 74HC4020]
+
|[https://www.nxp.com/docs/en/data-sheet/74HC_HCT4020_CNV.pdf 74HC4020]
 
|Binary Ripple Counter
 
|Binary Ripple Counter
 
|U207 (2)
 
|U207 (2)
 
|-
 
|-
  
−
|[http://www.ti.com/lit/ds/symlink/lmz12001.pdf LMZ12001]
+
|[https://www.ti.com/lit/ds/symlink/lmz12001.pdf LMZ12001]
 
|Power Module
 
|Power Module
 
|U101 (1)
 
|U101 (1)
 
|-
 
|-
 
|}
 
|}
−
 
−
==Mechanical Info==
 
−
===Weight===
 
−
2.6 lbs
 
−
 
−
===Drawings===
 
−
* [[File:cu ettus octoclock cca.pdf]]
 
−
* [[File:cu ettus-octoclock.pdf]]
 
  
 
==Certifications==
 
==Certifications==
Line 100: Line 125:
 
* [[Media:OctoClock CoV.pdf]]
 
* [[Media:OctoClock CoV.pdf]]
  
−
==Firmware==
+
== Firmware ==
−
The OctoClock's firmware is divided into two image files: octoclock_bootloader.hex and octoclock_r4_fw.hex. All image files can be found [http://files.ettus.com/binaries/images/ here], in version-specific ZIP files. Download the version corresponding to the version of UHD that you're running. You must use at least version 3.9.2.
+
  
−
* Full instructions on updating the OctoClock's firmware is located here: http://files.ettus.com/manual/page_octoclock.html#upgrading_device
+
The OctoClock's firmware is divided into two image files: octoclock_bootloader.hex and octoclock_r4_fw.hex. All pre-built image files can be found [http://files.ettus.com/binaries/images/ here], in version-specific ZIP files. Download the version corresponding to the version of UHD that you're running. You must use at least version 3.9.2.
−
* Source of the firmware for the OctoClock is located at: https://github.com/EttusResearch/uhd/tree/master/firmware/octoclock
+
 
 +
* Full instructions on updating the OctoClock's firmware is located [https://files.ettus.com/manual/page_octoclock.html#upgrading_device here]
 +
* Source of the firmware for the OctoClock is located [https://github.com/EttusResearch/uhd/tree/master/firmware/octoclock here]
  
 
==Downloads==
 
==Downloads==
−
[https://www.ettus.com/content/files/OctoClock_Spec_Sheet.pdf OctoClock Spec Sheet]
+
[https://www.ettus.com/wp-content/uploads/2019/01/Octoclock_Spec_Sheet.pdf OctoClock Spec Sheet]
  
 
[http://files.ettus.com/manual/md_fpga.html FPGA Resources]
 
[http://files.ettus.com/manual/md_fpga.html FPGA Resources]
Line 117: Line 143:
  
  
−
==FAQ==
+
== FAQ ==
−
*'''What is the OctoClock'''
+
 
 +
* '''What are the OctoClock and OctoClock-G?'''
  
 
The OctoClock is a USRP-compatible accessory that allows you to easily synchronize up to 8 USRP radios. Multiple OctoClock devices can be combined for synchronization of larger numbers of USRP radios.
 
The OctoClock is a USRP-compatible accessory that allows you to easily synchronize up to 8 USRP radios. Multiple OctoClock devices can be combined for synchronization of larger numbers of USRP radios.
  
−
*'''When would I used the OctoClock'''
+
The OctoClock-G is an OctoClock with added GPSDO module.
  
−
The OctoClock is useful for synchronizing multiple USRP devices for high channel count systems.
+
In this FAQ we will use "OctoClock" to refer to either unless there is a specific need to use either name.
  
−
The following applications can benefit from OctoClock clock distribution:
 
  
−
*Direction Finding
+
* '''When would I used the OctoClock?'''
−
*Beamforming
+
−
*Adaptive Beamforming
+
−
*Multiple-In-Multiple-Out (MIMO) Prototyping
+
−
*Geolocation Systems that Use Time-Difference-of-Arrival (TDOA)
+
−
*Multi-Channel, Multi-Static, and Passive RADAR
+
−
*Multi-Band GPS Record and Playback
+
−
*Multi-Band Cellular Monitoring
+
  
−
Essentially, anything that requires from synchronization or the distribution of timing information would benefit from the use of the OctoClock.
+
The OctoClock is useful for synchronizing multiple USRP devices for high channel count systems.
  
−
*'''Are there example applications that could benefit from the OctoClock'''
+
The following applications can benefit from OctoClock clock distribution:
  
−
32-Channel Phased-Array Receiver Built with QR210 - OctoClock a Component in the System
+
* Direction Finding
 +
* Beamforming
 +
* Adaptive Beamforming
 +
* Multiple-In-Multiple-Out (MIMO) Prototyping
 +
* Geolocation Systems that Use Time-Difference-of-Arrival (TDOA)
 +
* Multi-Channel, Multi-Static, and Passive RADAR
 +
* Multi-Band GPS Record and Playback
 +
* Multi-Band Cellular Monitoring
  
−
Afford 8x8 MIMO Testbed
+
Essentially, anything that requires synchronization or the distribution of timing information would benefit from the use of the OctoClock.
  
−
Share your applications with us and we will add them to the list.
 
  
−
*'''How does the OctoClock work'''
+
* '''How does the OctoClock work?'''
  
 
The OctoClock accepts 10 MHz and PPS signals from an external source. Active circuits are used to amplify and split the signals 8-ways. Matched-length traces minimize phase differences between all 10 MHz and 1 PPS outputs
 
The OctoClock accepts 10 MHz and PPS signals from an external source. Active circuits are used to amplify and split the signals 8-ways. Matched-length traces minimize phase differences between all 10 MHz and 1 PPS outputs
Line 153: Line 178:
 
The OctoClock-G includes an internal GPSDO (GPS Disciplined Oscillator) which provides an internal source for 10 MHz and PPS from an OCXO high precision oscillator.  Add a GPS antenna  (optional) with a clear view of the sky for GPS Disciplining of the OCXO that futher enhances frequency accuracy of the OCXO and global time synchronization.
 
The OctoClock-G includes an internal GPSDO (GPS Disciplined Oscillator) which provides an internal source for 10 MHz and PPS from an OCXO high precision oscillator.  Add a GPS antenna  (optional) with a clear view of the sky for GPS Disciplining of the OCXO that futher enhances frequency accuracy of the OCXO and global time synchronization.
  
−
*'''Where can I find user manuals for the OctoClock and USRP'''
 
  
−
Here is helpful document. Sync. and MIMO w/ the USRP
+
* '''Does the OctoClock-G provide power for using an active GPS antenna?'''
  
−
Also, here is some documentation on how to use UHD™ to interact with multi-USRP systems.
+
Yes. The OctoClock-G's GPSDO module is the [https://www.jackson-labs.com/index.php/products/lc_xoJackson Labs LC_XO], which can provide 5 V at up to 50 mA to the external active GPS antenna. The non-G OctoClock does not have this GPSDO module, and thus cannot use a GPS antenna if attached, nor provide power to one if attached.
  
−
*'''What USRP model do you recommend for MIMO systems'''
 
  
−
The USRP N200 or N210 and USRP X300 or X310 are recommended for building high channel count and MIMO systems. These models provide external PPS and 10 MHz reference inputs.  The USRP N200 and N210 support the USRP MIMO cable.
+
* '''Where can I find user manuals for the OctoClock and USRP?'''
 +
 
 +
[https://kb.ettus.com/Synchronization_and_MIMO_Capability_with_USRP_Devices Synchronization and MIMO Capability with USRP Devices]
 +
 
 +
[https://files.ettus.com/manual/page_multiple.html UHD Manual: Multiple USRP configurations]
 +
 
 +
 
 +
* '''What USRP model is recommended for MIMO systems?'''
 +
 
 +
The USRP N200 + N210, N310, N320 + N321, X300 / X310 are recommended for building high channel count and MIMO systems. These models provide external PPS and 10 MHz reference inputs.  The USRP N200 and N210 support the USRP MIMO cable.
  
 
The USRP B100, B200, B210, E100, E110, and E310 can be synchronized with 10 MHz/PPS but are not phase coherent MIMO capable devices. The USRP1 cannot be synchronized with 10 MHz/PPS.
 
The USRP B100, B200, B210, E100, E110, and E310 can be synchronized with 10 MHz/PPS but are not phase coherent MIMO capable devices. The USRP1 cannot be synchronized with 10 MHz/PPS.
  
−
*'''How does the automatic switchover functionality work'''
 
  
−
When using the OctoClock-G, the Internal/External switch on the front panel allows the user to choose between the  internal GPSDO and external source 10 MHz/PPS source.  If the selected sournce is not availble, the device will automatically switch over to the backup frequency source.  When switchover is active the corresponding LED indicator will illuminate.
+
* '''How does the automatic switchover functionality work?'''
 +
 
 +
When using the OctoClock-G, the Internal/External switch on the front panel allows the user to choose between the  internal GPSDO and external source 10 MHz/PPS source.  If the selected source is unavailable, the device will automatically switch over to the backup frequency source.  When switchover is active the corresponding LED indicator will illuminate.
  
 
If neither source is present, the internal, external and status LEDs will not be illuminated and the user will not received valid 10 MHz/PPS outputs.
 
If neither source is present, the internal, external and status LEDs will not be illuminated and the user will not received valid 10 MHz/PPS outputs.
  
−
*'''What do the LED indications mean'''
 
  
−
The following list describes the behavior when each of the 6 LED status indicators is illuminated:
+
* '''What do the LEDs status indicators mean?'''
 +
 
 +
The following list describes the behavior when each of the 6 LED status indicators is illuminated:
 +
 
 +
* Internal - internal GPSDO is selected and present.
 +
* External - external source is selected and present
 +
* Status - Either the internal GPSDO or external source is selected. If neither source is present this LED will turn off (no signals are output).
 +
* PPS - selected PPS pulse high.
 +
* GPS Locked - GPS is receiving signals and has valid time/position lock.
 +
* Power - Power is applied.
  
−
*Internal - internal GPSDO is selected and present.
 
−
*External - external source is selected and present
 
−
*Status - Either the internal GPSDO or external source is selected. If neither source is present this LED will turn off (no signals are output).
 
−
*PPS - selected PPS pulse high.
 
−
*GPS Locked - GPS is receiving signals and has valid time/position lock.
 
−
*Power - Power is applied - smoke is still inside.
 
  
−
*'''What are the input and output specifications'''
+
* '''What are the input and output specifications?'''
  
−
*10 MHz Input – 0-10 dBm
+
* 10 MHz Input – 0-10 dBm
−
*10 MHz Outputs - ~1.4 Vpp Square Wave, Impedance 50 ohm nominal
+
* 10 MHz Outputs - ~1.4 Vpp Square Wave, Impedance 50 ohm nominal
−
*1 PPS Input - Logic-level pulse, 2.5V - 5V
+
* 1 PPS Input - Logic-level pulse, 2.5 V - 5 V
−
*1 PPS Outputs - Logic-level pulse, 2.5V - 5V
+
* 1 PPS Outputs - Logic-level pulse, 2.5 V - 5 V
  
−
*'''What is the function of the Ethernet port'''
 
  
−
Currently, the Ethernet port is non-functional. In the future the Ethernet port may be used to provide a method for reading GPS time and NMEA sentences.
+
* '''What is the input voltage rating?'''
  
−
*'''What is the input voltage rating'''
+
The OctoClock can be powered at any voltage between 6 and 15 Vdc.
  
−
The OctoClock can be powered at any voltage between 6 and 15Vdc.
 
  
−
*'''Are the design files open source'''
+
* '''Are the design files open source?'''
  
−
As with all of our products, the driver code is free & open source, and can be found in our UHD repository. The schematics are also available.
+
As with all of our products, the driver code is free & open source, and can be found in [https://github.com/EttusResearch/uhd/tree/master/firmware/octoclock our UHD repository]. The [https://kb.ettus.com/OctoClock_CDA-2990#OctoClock schematics are also available].
  
  
 
[[Category:Hardware Resources]]
 
[[Category:Hardware Resources]]

Latest revision as of 09:14, 3 September 2024

Device Overview

The OctoClock CDA-2990 is an affordable solution for high-accuracy time and frequency reference distribution. The OctoClock accepts 10 MHz and PPS signals from an external source, and distributed each signal 8 ways. The OctoClock is a useful accessory for users that would like to build multi-channel systems that are synchronized to a common timing source.

The OctoClock-G CDA-2990 provides the same functionality as the OctoClock CDA-2990, but includes a GPSDO that can be used to produce internal 10 MHz and PPS signals, as well as a front-panel switch to select between internal and external sources for the signals. Note that both signals must come from the same chosen source: either both are generated internally from the GPSDO, or both are provided from the external inputs.

Note: Both of the CDA-2990 devices are functionally identical to the previous generation OctoClock, which contained an Ettus Research logo.

Key Features

  • 8-Way Time and Frequency Distribution (1 PPS and 10 MHz)
  • Convenient Solution for Multi-Channel Synchronization
  • Use with MIMO Capable N-Series Devices for Coherent System
  • External 10 MHz/1 PPS Source Required
  • 19" Rackmount – 1U
Product octoclock.jpg
octoclock2.png

Signal Levels

10 MHz output 
square wave with close to 50% duty cycle; 1.25 Vpp at 50 ohms, 3.3Vpp at 1M ohms
1 PPS output
20% duty cycle square wave with amplitude 5 V
10 MHz input 
0-20 dBm
1 PPS input
2.5-5 V
octoclock1.png
octoclock3.png

Physical Specifications

Dimension (1U Rackmount)

4 x 17.187x 1.75 inches

Weight

2.6 lbs

Drawings

CAD/STP Models

OctoClock CDA-2990

OctoClock CDA-2990

Environmental Specifications

Operating Temperature Range

  • 0-40 °C

Operating Humidity Range

  • 10% to 90% non-condensing

Input/Output Impedance

All RF Ports are matched to 50 Ohm with -10dB or better return loss generally. Detailed test is pending.

Ethernet Port

The Ethernet port on the OctoClock and OctoClock-G allows the device to be connected to the network. When connected, the uhd_find_devices utility can find any OctoClock devices on the network, and the device's firmware may be updated over Ethernet using the octoclock_burn_eeprom utility. In addition, with the OctoClock-G, NMEA strings may be obtained from the internal GPSDO via the UHD API. Note that there is no host CPU in the OctoClock, so it is not possible to SSH into the device.

Schematics

OctoClock

OctoClock Schematics

Key Component Datasheets

Part Number Description Schematic ID (Page)
ENC28J60−DIG Ethernet Controller U103 (1)
ATmega128 Microcontroller U102 (1)
LC_XO Spec Sheet Manual Jackson Labs LC_XO (OCXO) U206 (2)
SN74AUP1T57 VOLTAGE-LEVEL TRANSLATOR U204, U203 (2)
CDCE18005−PWR Output Clock Programmable Buffer U205 (2)
74HC4020 Binary Ripple Counter U207 (2)
LMZ12001 Power Module U101 (1)

Certifications

RoHS

As of December 1st, 2010 all Ettus Research products are RoHS compliant unless otherwise noted. More information can be found at http://ettus.com/legal/rohs-information

China RoHS

Management Methods for Controlling Pollution Caused by Electronic Information Products Regulation

Chinese Customers

National Instruments is in compliance with the Chinese policy on the Restriction of Hazardous Substances (RoHS) used in Electronic Information Products. For more information about the National Instruments China RoHS compliance, visit ni.com/environment/rohs_china.

Certificate of Volatility

OctoClock

Firmware

The OctoClock's firmware is divided into two image files: octoclock_bootloader.hex and octoclock_r4_fw.hex. All pre-built image files can be found here, in version-specific ZIP files. Download the version corresponding to the version of UHD that you're running. You must use at least version 3.9.2.

  • Full instructions on updating the OctoClock's firmware is located here
  • Source of the firmware for the OctoClock is located here

Downloads

OctoClock Spec Sheet

FPGA Resources

UHD Stable Binaries

UHD Source Code on Github


FAQ

  • What are the OctoClock and OctoClock-G?

The OctoClock is a USRP-compatible accessory that allows you to easily synchronize up to 8 USRP radios. Multiple OctoClock devices can be combined for synchronization of larger numbers of USRP radios.

The OctoClock-G is an OctoClock with added GPSDO module.

In this FAQ we will use "OctoClock" to refer to either unless there is a specific need to use either name.


  • When would I used the OctoClock?

The OctoClock is useful for synchronizing multiple USRP devices for high channel count systems.

The following applications can benefit from OctoClock clock distribution:

  • Direction Finding
  • Beamforming
  • Adaptive Beamforming
  • Multiple-In-Multiple-Out (MIMO) Prototyping
  • Geolocation Systems that Use Time-Difference-of-Arrival (TDOA)
  • Multi-Channel, Multi-Static, and Passive RADAR
  • Multi-Band GPS Record and Playback
  • Multi-Band Cellular Monitoring

Essentially, anything that requires synchronization or the distribution of timing information would benefit from the use of the OctoClock.


  • How does the OctoClock work?

The OctoClock accepts 10 MHz and PPS signals from an external source. Active circuits are used to amplify and split the signals 8-ways. Matched-length traces minimize phase differences between all 10 MHz and 1 PPS outputs

The OctoClock-G includes an internal GPSDO (GPS Disciplined Oscillator) which provides an internal source for 10 MHz and PPS from an OCXO high precision oscillator. Add a GPS antenna (optional) with a clear view of the sky for GPS Disciplining of the OCXO that futher enhances frequency accuracy of the OCXO and global time synchronization.


  • Does the OctoClock-G provide power for using an active GPS antenna?

Yes. The OctoClock-G's GPSDO module is the Labs LC_XO, which can provide 5 V at up to 50 mA to the external active GPS antenna. The non-G OctoClock does not have this GPSDO module, and thus cannot use a GPS antenna if attached, nor provide power to one if attached.


  • Where can I find user manuals for the OctoClock and USRP?

Synchronization and MIMO Capability with USRP Devices

UHD Manual: Multiple USRP configurations


  • What USRP model is recommended for MIMO systems?

The USRP N200 + N210, N310, N320 + N321, X300 / X310 are recommended for building high channel count and MIMO systems. These models provide external PPS and 10 MHz reference inputs. The USRP N200 and N210 support the USRP MIMO cable.

The USRP B100, B200, B210, E100, E110, and E310 can be synchronized with 10 MHz/PPS but are not phase coherent MIMO capable devices. The USRP1 cannot be synchronized with 10 MHz/PPS.


  • How does the automatic switchover functionality work?

When using the OctoClock-G, the Internal/External switch on the front panel allows the user to choose between the internal GPSDO and external source 10 MHz/PPS source. If the selected source is unavailable, the device will automatically switch over to the backup frequency source. When switchover is active the corresponding LED indicator will illuminate.

If neither source is present, the internal, external and status LEDs will not be illuminated and the user will not received valid 10 MHz/PPS outputs.


  • What do the LEDs status indicators mean?

The following list describes the behavior when each of the 6 LED status indicators is illuminated:

  • Internal - internal GPSDO is selected and present.
  • External - external source is selected and present
  • Status - Either the internal GPSDO or external source is selected. If neither source is present this LED will turn off (no signals are output).
  • PPS - selected PPS pulse high.
  • GPS Locked - GPS is receiving signals and has valid time/position lock.
  • Power - Power is applied.


  • What are the input and output specifications?
  • 10 MHz Input – 0-10 dBm
  • 10 MHz Outputs - ~1.4 Vpp Square Wave, Impedance 50 ohm nominal
  • 1 PPS Input - Logic-level pulse, 2.5 V - 5 V
  • 1 PPS Outputs - Logic-level pulse, 2.5 V - 5 V


  • What is the input voltage rating?

The OctoClock can be powered at any voltage between 6 and 15 Vdc.


  • Are the design files open source?

As with all of our products, the driver code is free & open source, and can be found in our UHD repository. The schematics are also available.

Retrieved from "https://kb.ettus.com/index.php?title=OctoClock_CDA-2990&oldid=6056"