Automotive Ethernet Testing
Automotive Ethernet Testing
Achieving Reliability and Interoperability
ADAS, smart safety systems, and human to machine subsystems generate vast amounts of data to transport throughout a vehicle. Furthermore, requirements for greater integration between vehicle subsystems are driving fundamental architectural changes: moving from simple ring networks to more complex topologies, including gateways connected to a backbone.
Automotive Ethernet stems from proven IT technology and serves the needs for both capacity and integration. Unlike non-automotive Ethernet, the automotive bus uses unshielded, single twisted-pair cabling designed for lower weight and cost. It uses PAM3 modulation to achieve high data rates and reliability.
The automotive standard has its origins in Ethernet, but incorporates significant changes at the physical layer to meet automotive requirements. The first version of the standard is known as BroadR-Reach and is being supplanted by the IEEE versions known as 100BASE-T1 (P802.3bw) and 1000BASE-T1 (802.3bp).
To insure the interoperability of hardware and assure reliable vehicle operation in diverse operating conditions, strict constraints are placed on signal levels, noise, and clock characteristics. The testing techniques specified by the standards, although well-established for stationary Ethernet networks, have created new design challenges for many automotive engineers accustomed to working with slower serial buses like CAN and LIN.
Validating your design
Once a prototype network device is built up, it’s time to ‘bring up’ the design and characterize it to make sure it’s within specification.
Tektronix oscilloscopes are an invaluable tool for bringing up and characterizing your Automotive Ethernet design.
- Complete characterization under different use cases with advanced measurements and analysis tools
- Automated measurements such as amplitude and time measurements, along with statistical analysis and histograms, are a good place to start to check signal quality
- Eye diagrams are the fastest way to evaluate PAM3 signaling for noise and signal integrity issues
- Jitter analysis tools provide complete profiles of master/slave clock jitter including Time Interval Error (TIE), and cycle-to-cycle, Rj/Dj measurements
Eye diagrams are the best way to view complex PAM3 waveforms
Speed debugging and troubleshooting
It’s to be expected that in complex networks systems or components sometimes fail, requiring speedy debug to root cause. Automotive Ethernet’s higher data rates and embedded clocking are sensitive to noise and power variations.
Engineers, used to evaluating waveforms as part of their troubleshooting procedure, often find the PAM3 signals more difficult to debug. Also, since automotive Ethernet is a bi-directional bus it can be more challenging to capture the exact signal of interest.
Tektronix oscilloscopes configured with advanced analysis software provide the tools required for quick and effective troubleshooting if you miss the mark on a spec.
- TIE and histograms to troubleshoot clock recovery problems
- Eye diagrams to quickly evaluate PAM3 signals
- Advanced jitter analysis to identify noise sources by determining whether the jitter is random or deterministic
- Extended triggering functionality
- FFT analysis to isolate sources of interference
Troubleshooting complex systems requires multi-channel measurements and capable signal integrity tools such as FFTs and jitter analysis.
Compliance with confidence
Automated tests such as this Power Spectral Density test, confirm compliance with the standard by comparing results to test limits.
With greater integration of subsystems into networked environments engineers have to provide verifiable, objective evidence that every device is interoperable; that an individual ECU will reliably communicate with any other ECU. Requirements also extend to EMI/EMC and ESD testing.
However, the adoption of more complex, high speed Mbps and Gbps serial technologies can be more challenging to test.
Tektronix has been involved in high-speed compliance testing for many years and is applying this expertise to testing newer technologies in automotive. Compliance solutions include support for 100BASE-T1 (802.3bpTM) and as well as BroadR-Reach. Both adhere to the testing requirements defined by the OPEN Alliance. Tektronix oscilloscopes and spectrum analyzers can also be applied for ESD and EMC testing.
Introducing Signal Separation for Automotive Ethernet Testing
Signal Characterization and Protocol testing of automotive Ethernet can create challenges from design to validation to maintenance. Seeing actual data between ECU#1 and ECU#2, assessing signal integrity in Full Duplex mode and examining Protocol data at the system level without breaking the cable add test complications, time and expense. Tektronix’ unique, patent pending, Signal Separation solution overcomes the shortcomings of current offerings in the market, enabling customers to:
- Separate traffic from ECU#1 and ECU#2 in Full-Duplex mode without having to cut cables or make hardware changes to the Ethernet cable
- Simultaneously display ECU#1 and ECU#2 Protocol decode data
- Perform Protocol decode in Full-duplex mode
- Automotive Ethernet PAM3 and Signal Separation Introduction
- Automotive Ethernet: See the True Signal
Automotive Ethernet Testing Solutions
Testing an automotive Ethernet often requires an oscilloscope, appropriate probes, a signal source, software and test fixtures. To meet your needs, Tektronix offers a full line of test solutions for Signal Quality and Compliance.
| Automotive Ethernet Test | Oscilloscope | Software | Probes | Signal Source | Fixture |
|---|---|---|---|---|---|
| Signal Quality Testing (Signal Separation, Protocol Decode, Signal Quality & Debug) |
5 Series MSO (Windows only) 6 Series MSO (Windows only) |
Option 5/6 -AUTOEN-SS: Signal Separation Option 5/6 -PAM3 (Automotive Ethernet Signal Analysis) Option 5/6 -SRAUTOEN1 (100BASE-T1 Protocol decode) Opt. 5/6 -DJA (Jitter Analysis) |
TDP1500 TCP0030A / P6022 |
ECU Dependent Contact Tektronix for information |
|
| Open Alliance TC8 PMA-Tx Compliance Testing | 5 Series MSO (Windows only) 6 Series MSO (Windows only) |
Opt. 5/6 -CMAUTOEN (1000BASE-T1/100BASE-T1 Compliance) Opt. 5/6 -DJA (Jitter Analysis) |
TDP1500 TDP3500 |
AWG5200 (RL & Distortion) AFG3152C (Distortion only) |
TF-XGbT TF-BRR-CFD Contact Tektronix for information |
| DPO70000C MSO / DPO70000 |
Opt. BRR (1000BASE-T1/100BASE-T1 Compliance) Opt. DJA (Jitter Analysis) |
Automated testing software may be installed on a new instrument, added to an existing instrument, or shared among a fleet of scopes in the same series. Contact Tektronix for more information.
Featured Content
Characterizing and Troubleshooting Jitter with Your Oscilloscope
Gives examples of jitter analysis, from basic analysis using frequency and Time Interval Error (TIE) measurements, to more advanced jitter decomposition techniques to help isolate the sources of jitter. Shows examples of jitter measurements using the 5 Series Mixed Signal Oscilloscope on unmodulated clocks, spread spectrum clocks, and serial data.
Validate automotive Ethernet performance and standards compliance
5 Series MSO Mixed Signal Oscilloscope with 2 GHz bandwidth
- Automotive Ethernet compliance test package automates testing per industry standards
- Integrated eye diagrams and optional jitter analysis help validate signal integrity
- Up to 8 input channels
- 15.6” high definition pinch/swipe/zoom touchscreen provides more analysis area
Automotive Ethernet testing, low noise, and up to 8 GHz bandwidth
6 Series MSO Mixed Signal Oscilloscope
- Automotive Ethernet compliance test package automates testing per industry standards
- Integrated eye diagrams and optional jitter analysis help validate signal integrity
- Exceptional noise performance, especially at high sensitivity
- 15.6” high definition pinch/swipe/zoom touchscreen
Automotive Ethernet testing and up to 20 GHz bandwidth
MSO/DPO70000C Series Oscilloscope
- Automotive Ethernet compliance test package automates testing per industry standards
- Broadest range of standards support, including MIPI, DisplayPort, HDMI, PCIe Gen3/Gen4, SATA/SAS, USB3.1, Type-C, and 10/100BaseT to 10G/100G Ethernet
Facing challenges in other connected car applications?
Library
| Title |
|---|
| Automotive Ethernet: See the True Signal As the move toward Automotive Ethernet technology in vehicles accelerates, comprehensive design validation is vital to ensure interoperability and reliable operation across multiple ECUs. This application note provides information on Automotive Ethernet, full-duplex communication, the need to separate master and slave signals, signal separation testing methodologies, and a comparison of the current directional coupler insertion method and the Tektronix new signal separation method. |
