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DXD/PTP/GPS User Manual (rev 2.10)

Page 5

3. Reference & Sync Menus 

3.1 REFERENCE MENU (MENU 1.1) 

Two new choices are available for reference selection based on the installed options: GPS and PTP Mode. 

GPS

 is straightforward, like the other references available to the DXD-8. When selected, it becomes the DXD reference. If GPS 

reception drops out, the DXD will switch to internal crystal until GPS reception resumes. The transition occurs smoothly to avoid 
sync shocks. 

When using GPS, it is recommended to install the optional OCXO oscillator for better tracking during long dropouts (see ch 7). 

PTP Mode

 is a little different. Selecting PTP Mode as the reference is required for the DXD-8 to be a PTP slave, i.e. ‘referenced’ 

to a PTP Grandmaster. However, selecting PTP Mode means that the DXD-8 will participate in the PTP Grandmaster selection and 
will either be a PTP Slave or the Grandmaster based on the outcome of the BMCA (see 3.5). Explanatory text has been added to 
the REFERENCE menu when PTP Mode is activated. 

NOTE: When PTP Mode is selected, the PTP port needs to be turned on (menu 5.1). If not, 
the DXD-8 will lock to its internal crystal and a ‘PTP

 

NO

 

PORT’ warning message will appear 

in the middle of the display. The LOCK bar at the bottom of the Main Rotation display will 
also indicate NO PORT (for more information, see chapter 22.Troubleshooting). 

• LOCAL REF WHEN GM: 

When PTP Mode is selected , if GPS is available, this fields enables GPS to be set as the reference when the DXD-8 is the Grandmaster. 
Enabling this field will announce the DXD-8 as GPS referenced, giving it a better chance at being selected by the BMCA. 

This field only appears if the optional DXD/GPS receiver has been installed. 

3.2 SYNC PARAMETERS (MENU 1.2) 

New parameters are available in this menu with the PTP or GPS options. 

BNC INPUT TIME JAM SOURCE:

 Selects the source of a Time Jam (see 8.2). 

BNC INPUT TIME JAM RESYNC:

 Used for a manual Time Jam (see 8.2) 

PTP

 

JUMP THRESHOLD:

 When the difference between the internal TOD and the PTP reference is above the value 

entered, the DXD will not attempt a smooth transition (slew) but will instead jump instantly to the new time. 
Value can be adjusted from 5 msec to 15 sec, or set to  ‘Never’. Default value is 5

 

msec. 

4. PTP Menus 

4.1 PORT MODE (MENU 5.1) 

This menu allows you to have PTP turned on or off. 

•When OFF, PTP is disabled (default value). 
•When ON, the port is enabled. 

With the port enabled, the DXD-8 automatically becomes a candidate for PTP Grandmaster. Keep in mind however that it’s 
ability to be a PTP slave depends on the reference selection in menu 1.1: 

-

if PTP Mode is selected: the DXD-8 can become a PTP slave. 

-

if another reference is selected: the DXD-8 can only be a PTP master, not a PTP slave. 

NOTE: When the port is enabled and a reference other than ‘PTP Mode’ is selected menu 1.1, if the BMCA selects another 
unit as PTP Grandmaster, the port will go in the PASSIVE state. 

Summary of Contents for DXD/GPS

Page 1: ...k DXD OCXO OCXO option for the DXD Universal Clock Operations manual Version 2 10 January 2021 All materials herein Brainstorm Electronics Inc Brainstorm Electronics reserves the right to change or mo...

Page 2: ...6 GPS Menus 8 6 1 SATELLITES SELECTION MENU 6 1 8 6 2 GPS SETTINGS MENU 6 2 8 6 3 ADVANCED GPS SETTINGS MENU 6 3 8 7 DXD OCXO 9 8 Time of Day 9 8 1 RTC Real Time Clock 10 8 2 Time Jam 10 8 2 1 TIME JA...

Page 3: ...9 15 Typical PTP use 20 15 1 HYBRID SYNC GENERATOR ACCEPTING MULTIPLE REFERENCES 20 15 2 DISTRIBUTED PTP VS INDIVIDUAL GRANDMASTERS WITH GNSS 21 16 Guidelines for con fi guring PTP Precision Time Prot...

Page 4: ...a series of 4 numbers separated by periods This key is only valid for the DXD 8 with the serial number used when you placed the order Note that PTP is optional on the DXD 8 only A feature key is not r...

Page 5: ...ng LOCAL REF WHEN GM When PTP Mode is selected if GPS is available this fields enables GPS to be set as the reference when the DXD 8 is the Grandmaster Enabling this field will announce the DXD 8 as G...

Page 6: ...a quick set up This menu gives you the option to set the timing values to the pro fi le default values 4 4 PORT TIMING MENU 5 4 Announce Interval 3 to 4 1 8sec 16sec Sets the rate at which the master...

Page 7: ...in your DXD an antenna will need to be connected to the receiver s SMA connector an antenna is not included with the DXD GPS The cable needs an SMA Male connector on the DXD side Ideally the antenna s...

Page 8: ...sideration as it can not only impact the signal strength but also cause a delay in the signal Under typical conditions however the expected cable delay is negligible in the nanoseconds range The follo...

Page 9: ...e reference sources include time and rate information GPS and PTP for example carry precise time and date information as well as frequency However traditional reference signals such as video sync or w...

Page 10: ...nd wanting all of the cross frame outputs 25 etc to be in correct phase and epoch as well as wordclocks and AES In a primarily legacy application this is the way to increase the number of legacy outpu...

Page 11: ...to use Local Time instead while others may even prefer different standards for different times Be aware that even though the time source may give Time Of Day it may not correspond to the time indicate...

Page 12: ...on Jan 1 1970 This process occurs everyday at the same time as set in the DAILY JAM TIME fi eld Daily Jam Time The value entered in the DAILY JAM TIME field is the amount of time after midnight local...

Page 13: ...to LOCKED GRANDMASTER In case the DXD is or becomes a PTP Salve when locked it changes to LOCKED PTP SLAVE Note that if another source was selected in the reference menu such as Video Sync and the DXD...

Page 14: ...lock and the Grandmaster in sec Additional times may appear on this page such as Time Code based on the installed options 11 2 2 GPS RECEIVER STATUS PAGE The GPS RECEIVER status page displays the foll...

Page 15: ...as the ability to clock to a non Dante PTP v2 clock AVB Audio Video Bridging is a set of IEEE standards that facilitate the transport of high performance audio and video on a LAN One of those standard...

Page 16: ...suited clock is found it will become the Grandmaster 12 6 SYNCHRONIZATION There are several different PTP messages used during synchronization sequenced as follows 1 The grandmaster sends a Sync messa...

Page 17: ...clocks on a single PTP communication path must use the same method to measure the time delay 12 8 TYPES OF CLOCKS IEEE 1588 de fi nes three different types of clocks Ordinary Clock OC Boundary Clock...

Page 18: ...ate of the port can change The BMCA determines what unit becomes the Grandmaster If the current Grandmaster disappears or looses GPS another Grandmaster is selected For more on the Grandmaster selecti...

Page 19: ...it has been set by the operator 14 1 JUMP TO RELOCK When the time difference detected between the external PTP GM and the DXD System Time is above the Jump Threshold value the DXD will jump to the ne...

Page 20: ...t all equipment could be kept perfectly synchronized But for added fl exibility the DXD s can also be set up to lock to any legacy sync or to PTP as illustrated below These choices are available in th...

Page 21: ...TP slaves to an external Grandmaster in the second illustration the DXD 8 s are all Grandmaster for their networks and each is locked to GNSS This second solution is particularly useful when distances...

Page 22: ...ith any other domain number will be ignored menu 5 2 Ports Timing per IEEE 1588 all devices on a PTP domain must have the same value set for these ports timing Announce Interval Announce Receipt Timeo...

Page 23: ...GMPv2 On larger networks a router is required to manage multicast group membership Switches that support IGMP snooping are also recommended 17 Troubleshooting Error Warning Messages 17 1 PTP NO PORT W...

Page 24: ...3 Menu 5 1 If PTP was selected TIME JAM BNC INPUT will automatically show in menu 5 1 in blue blue status information The words Time Jam will also appear on the REFERENCE line at the bottom of the ma...

Page 25: ...the ribbon cable to J23 the GPS connector on the motherboard B J23 is the designator number on both DXD 8 and DXD 16 PCB As always with ribbon cables make sure the connectors are properly oriented do...

Page 26: ...Including cable loss Low Gain mode FLNA High 3 For best jammer resistance and lower power consumption use 10 dB lower gain than the max gain 18 3 2 RECOMMENDED PASSIVE ANTENNA 1 High Gain mode FLNA Op...

Page 27: ...TIMEOUT 3 announce intervals SYNC INTERVAL 1 sec log 0 MINIMUM DELAY REQUEST INTERVAL 1 sync interval GLONASS Yes GALLILEO No QZSS LIC A Yes SBAS QZSS LIS SBAS DIF FIX ANTENNA CABLE DELAY 0 ANTENNA H...

Page 28: ...Page 28 DXD PTP GPS User Manual rev 2 10...

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