1. Expanding White Rabbit into the Test and Measurement World
Rodney Greenstreet and Leif Johansson
National Instruments

2. Our Mission for Success
Supplier
Success
Employee
Customer
Shareholder
We create innovative computer-based products that improve everyday life by improving technology.
We give our customers a better solution for measuring and automating the world around them.
National Instruments Confidential

3. 30 Years of NI Timing and Synchronization Innovation
GPIB Group
Execute Trigger (1978)
LabVIEW
FPGA
Timekeeper
System Timing
Controller ASIC(STC)
PXI Slot 2
System Timing
IEEE 1588v1
Synchronization
and Memory
Core (SMC)
IEEE 1588v2
White
Rabbit
Real-Time System
Integration (RTSI) Bus
Timing I/O
ASIC (TIO)
GPS
IRIG-B
1986
1994
1998
2003
2006
2011
Compact
RIO
PXI
Express
PXI Platform
Desktop Computers
National Instruments CONFIDENTIAL

4. Real-Time System Integration (RTSI)
National Instruments CONFIDENTIAL

5. PXI Combines Standard Technologies
National Instruments Leadership Seminar
April, 2002
PXI Combines Standard Technologies
PXI backplane
Bus Technology
Timing
Synchronization
PXI controller
OS Technology
ADEs
Multicore
Chassis – DC and AC Power
PXI (PCI eXtensions for Instrumentation) is a rugged PC-based platform for measurement and automation systems. PXI combines PCI electrical-bus features with the rugged, modular, Eurocard mechanical-packaging of CompactPCI, then adds specialized synchronization buses and key software features. This makes it both a high-performance and low-cost deployment platform for measurement and automation systems. These systems serve applications such as manufacturing test, military and aerospace, machine monitoring, automotive, and industrial test. Developed in 1997 and launched in 1998, PXI was introduced as an open industry standard to meet the increasing demands of complex instrumentation systems. Today, PXI is governed by the PXI Systems Alliance (PXISA), a group of more than 65 companies chartered to promote the PXI standard, ensure interoperability, and maintain the PXI specification. For more information on the PXISA, including the PXI specification, refer to the PXISA Web site at
The chassis provides the rugged and modular packaging for the system. Chassis generally range in size from 4-slots to 18-slots, and also are available with special features such as DC power supplies and integrated signal conditioning. The chassis contains the high-performance PXI backplane, which includes the PCI bus and timing and triggering buses. These timing and triggering buses enable users to develop systems for applications requiring precise synchronization. For more information on the functionality of the PXI timing and triggering buses, refer to the PXI Hardware Specification at
As defined by the PXI Hardware Specification, all PXI chassis contain a system controller slot located in the leftmost slot of the chassis (slot 1). Controller options include remote control from a standard desktop PC or a high-performance embedded control with either a Microsoft operating system (such as Windows 2000/XP) or a Real-Time operating system (such as LabVIEW Real-Time).
Master Timing Slot
Peripheral Slots
National Instruments CONFIDENTIAL

6. PXI Trigger Bus (8 TTL Triggers)
100 MHz
Differential CLK
PXI Express
Star
Trigger
10 MHz
CLK
PXI Express
Controller
System
PXI Express
Peripheral
Hybrid
PXI Express
Peripheral
Hybrid
PXI Express
Peripheral
Hybrid
PXI Express
Timing Slot
System
Peripheral
PXI-1
Differential Star
Triggers
We have extended these concepts into our PXIe platform which uses PCI express. This platform includes a 100MHz System Differential Clock that is tightly constrained as well as 3 pairs of matched trace length differential star triggers to each slot.
PXI Trigger Bus (8 TTL Triggers)

7. Synchronizing Multiple Chassis (Channel Expansion)
These concepts work really well when you are in the same PC or PXI chassis. However, when you want to synchronize multiple PCs or chassis, you have the problem of having to scale over distance. One way to do this is to share the same signals over a different fabric.
National Instruments CONFIDENTIAL

8. Boeing: Minimizing Ground Noise
An example of this approach was used by Boeing to isolate and minimize ground noise of their airplanes. They wanted to use a microphone array to map the acoustic patterns…

9. Both in a wind tunnel…you can see the DSA system in the upper right and a model of their plane. And take that to full scale…

10. Full Scale Static Engine Test Installation
8x 300 m Fiber
In Control Room
This is another example where the same architecture was deployed in a full scale static engine test of the modified GE B. For full-scale tests, the frequency of interest would be no higher typically than 6 kHz which doesn’t require such a high sampling rate. The PXI chassis are placed behind the engine to cut down on cable lengths for measuring the jet engine plume, but the controllers are located in the control shed 300 m. away.
By careful design and implementation, Boeing was able to develop a high-end, low-cost data acquisition system with virtually unlimited channel expansion capability. This type of instrumentation helps them make good on their commitment to reduce noise emissions on their existing and new airplanes. This same type of distributed architecture can be used for making measurements on a variety of large structures where the sampling rates are often much lower.
395 Channels kS/s

11. Synchronized Microphone Array
To an actual runway. The had 400+ microphones that needed to be very tightly synchronized over a relatively large area.

12. Flyover Test Installation
100m
427 Channels kS/s
405 Low Cost Microphones
100m
8x 200m Fiber
Acoustic beam forming can be used in aircraft pass by noise tests to measure and distinguish engine and airframe noise sources in addition to testing quiet flight operation procedures. The use of phased arrays of microphones in the study of noise sources is being more widely used and should increase as the cost of instrumentation goes down. When properly used, arrays can be used to extract noise source distribution on full-scale and wind tunnel models.
With more channels, Boeing has been able to get higher resolution to distinguish noise sources. This information can be used to make design or operational changes. Their ultimate goal is to increase the channel count to over 1,000 channels. The flyover noise map with a phased array “acoustic camera” identifies opportunities for noise source reductions and distinguishes between engine and airframe sources.
In the first stage of the project in 2001, Boeing deployed a system that could handle a microphone array up to 264 channels. They ran into channel bandwidth limitations in the total number of channels that their system architecture allowed. The system required a centralized data system architecture where all the chassis had to be co-located which required over 30 miles of cable They also faced challenges in synchronizing multiple instrumentation chassis, the cost per channel, the dynamic range as well as the data turnaround (time to retrieve acquired data).

13. Synchronization Technologies
Precision
10-12 sec
Signal-based
On-chip
PXI Multichassis
PXI
Time-based
NTP
GPS
IEEE-1588
TCP/IP Messages
IRIG-B ?
10-9 sec
10-6 sec
10-3 sec
This precision vs. distance curve illustrates the synchronization performance and distance at which various synchronization technologies can achieve. So far, we have covered what we have termed signal-based synchronization which can achieve picoseconds within a chassis to sub-ns to out about 200 meters. This limitation is due to signaling loss over a copper medium.
What if you need tight synchronization on a much larger scale, like CERN does.
sec
<10-4m
10-2m
100m
101m
102m
103m
104m
105m
Global
Proximity
National Instruments CONFIDENTIAL

14. … Ethernet (1588) GPS Etc. Signal-Based
Share Physical Clocks / Triggers
Time-Based
Generate Signals
Share Time
Generate Signals
The beauty of sharing time is that by compensating for the path delay, whether your I/O is right next to each other or across very large distances you don’t incur proportional skew.
Ethernet (1588)
GPS
Etc.

15. Using Time-Based Synchronization
Time Reference
Interact w/ Time
GPS
FPGA-based
TimeKeeper
1588
I/O
Timestamping
Clock / Trig Gen
Supports multiple time references
Servo FPGA timekeeper to selected time reference
IRIG
DC or AM
PPS

16. Donghai Bridge - Structural Health Monitoring with PXI
Bridge Requirements
20-mile long, operating in harsh conditions
Long-term vibration monitoring with low-maintenance
High-level software to manage, analyze, and report on entire scale
Another application where GPS is critical is the structural health monitoring system of the Donghai bridge in the East China Sea. This bridge is over 20 miles long and the engineers were tasked with creating a long-term vibration monitoring system. Once again, it’s not feasible to share timing signals across these types of distances. The system was implemented using 14 PXI systems synchronized to GPS and it has been operating 24x7 for the last 2 years.
Solution
14 PXI systems synchronized over GPS
Continuous 24x7 operation for over 2-years
Structural Health Monitoring of the Donghai Bridge with NI LabVIEW and PXI
National Instruments Confidential

17. Next Gen Synchronization
NEW!
Next Gen Synchronization
GPS
1588
&
FPGA-based
TimeKeeper
Precision
TimeKeeper
Sync’d PXI_CLK10
1588
Sync’d DDS clock
Timestamping
Clock / Trig Gen
Timestamping
Supports multiple time references
Servo FPGA timekeeper to selected time reference
IRIG
DC or AM
Clock Generation
PPS

19. Next Steps… Action Item Target
NI WR Prototype: Start verification and validation.
May – 2012
Environmental Testing: Characterize environmental effects on link asymmetries.
June – 2012
Ensure WR Interoperability: WR Plug fest?
Aug – 2012
Ensure 1588 Interoperability: Test switch, spec board, and NI board at ISPCS 2012.
Sept – 2012
EISCAT Technology Demonstration: Demonstrate phased array measurements using WR.
Oct – 2012
Environmental Testing
Interoperability
Prototype of NI WR Board
1588 Plugfest testing

20. Standardization Efforts
Standardization promotes adoption

21. Why ?
Companies / Organisations are more inclined to invest if
They feel they have a stake in the technology, such as membership is a legitimate standards body
They know that no one party can unilaterally changed the spec, and hence put at risk their product investments
They know they have a better chance of success if they can interoperate with other companies' products
They feel more secure in their own investments by seeing others' investments
They are confident there is an enforcement policy on intellectual property ownership

22. Possible solutions platforms
ITU
IEEE
WR Consortium

23. Acceptance Criteria Broad Market Potential Compatibility
Distinct Identity
Technical Feasibility
Economic Feasibility

24. The Spec: White Rabbit Specification
Update and freeze to set expectations
Need for quantitative spec’s for
Timing
Sync

25. Need working group focusing on this
Long time frame to end result
Volunteers?