Tektronix’ Chris Godfrey on automotive electronics design and test
Q: Why does Tektronix see the automotive industry as an area of focus and innovation?
A: In its 130-year history, the automotive industry has never experienced a revolution such as is currently unfolding. Driven by electrification, automation, connectivity and mobility, manufacturers are having to re-evaluate hitherto unquestioned practices and technologies. Indeed, the very foundation of the car is mutating from a mechanical device to a “computer on wheels,” driven by the rapid advances in electronics.
As electronics continue to play a more and more important role in vehicles, the automotive industry is beginning to look very much like other more disruptive electronics segments. For instance, an automated vehicle could be equipped with 50 different sensors in 15 sensor sets will generate approximately 4 terabytes of data per day. To accommodate this, data rates are increasing from 10 Mb/s to 100 Mb/s to 1000 Mb/s to 2500 Mb/s to 5 Gb/s and standards from computer and consumer electronics are being adapted for automotive to accommodate higher data volume, and more devices while maintaining low latencies.
Learning to design high-performance systems while maintaining quality and reliability throughout the supply chain represents a daunting challenge, but one that Tektronix is well-equipped to help automotive electronics engineers overcome.
Q: How is electronics changing the automobile industry?
A: The industry is broadly facing pressure to move advanced electronic systems from research labs or exclusive small-volume applications into the mainstream. Government bodies responsible for highway and transportation safety at both regional and national levels are understandably excited about the prospect for Advanced Driver Assist Systems (ADAS). These groups see driver assistance technologies and especially more advanced automation as a way to significantly reduce injuries and fatalities caused by driver error.
And while this enthusiasm may be well-intentioned, there’s also the very real risk that manufacturers will attempt to bring systems to market before they are truly ready – all in an effort to differentiate products, win market share, appease stake holders and address government mandates. From the perspective of automotive electronics engineers, there’s no time to waste and speed is absolutely of the essence. It’s therefore vital that everyone in the electronics industry – including test & measurement – do everything we can to ease the pressure these engineers are facing by optimizing tools for speed, ease of operation and productivity.
Q: How is the growing role of electronics in automobiles impacting the various standards?
A: Most automotive electronics engineering has involved use of the CAN bus which was designed to transmit control-traffic between ECUs within the vehicle at maximum bus speeds of about 1 Mb/s with data packet payloads of up to 8 bytes. To keep up with the significant increase in data, CAN has undergone protocol modifications to become CAN FD (Flexible Data Rate) with the maximum bit rate increased to 15 Mb/s, and the payload improved to about 64 bytes.
At these rates CAN still cannot cope with imaging systems such as LIDAR and cameras. To support these data intense systems the industry has developed several alternatives including:
- FlexRay which has a higher maximum data rate and tight latency and time characteristics which make it ideal for ’drive-by-wire’ applications where deterministic performance is critical.
- More recently manufacturers have adapted the Ethernet standard as an automotive solution which can deliver high-performance bandwidth coupled to a low-cost single unshielded “twisted pair cables.” The technology is specifically engineered to meet the stringent in-vehicle requirements of the automotive industry and optimized for multiple in-car applications. The automotive-Ethernet qualified technology is capable of delivering a high-performance bandwidth of 100 Mb/s. Now emerging on scene is early development with 1000 Mb/s to address the growing need for higher data bandwidth and interest in extending this to 10 Gb/s.
- Initially targeting multimedia, the Media Oriented Systems Transport (MOST) consortium based in Karlsruhe, Germany, has created the MOST150 which is capable of transmitting 150 Mb/s. This additional bandwidth also makes MOST150 ideally suited for driver-assistance technologies such as lane-departure warning, camera systems and adaptive cruise control.
- Another system not explicitly developed for automotive applications but seeing active use is Low Voltage Differential Signaling (LVDS). It initially offers a high speed signaling standard with a bandwidth of up to 655 Mb/s (extending to Gbps) that uses a twisted pair of copper cables or coax cables. This high speed makes LVDS an attractive option for automotive camera manufacturers.
- For high data rate applications above 1 Gbps, there are other serial bus technologies. Several include APIX supporting 3 Gbps, FBDLink-III 4.16 Gbps and GMSL 3.12 Gbps data bandwidth.
Although a mixed signal oscilloscopes and bus-specific-triggers make it possible to isolate much of what engineers are looking for, and to time correlate with external events, the complexity and safety critical nature of this testing places an additional strain on resources. And, as the data rate increases, so too does the prospect of an oversight which could compromise the function of the network.
Q: What does all this mean to automotive engineers from a test & measurement perspective?
The key in trends in the industry all depend on test and measurement to be successful. These include higher bandwidths, the need for low latencies and the ability to support more data-producing devices because of initiatives ranging from “the connected car” to autonomous driving to features that improve safety such as lane-departure system.
Greater integration between subsystems is driving fundamental architectural changes that require new strategies as the industry moves from isolated systems to networked systems, including gateways connected to a backbone. Subsystems are generating massive data which has to be moved rapidly and without errors throughout the car. These increased speeds and associated complexity means that automotive engineers will have to learn new tools and techniques and move to higher-performance test instrumentation. It’s important, however, for test and measurement suppliers to reduce the inherent complexity involved and shorten the time to insight.
Q: What are some example of how Tektronix supports automotive engineers?
A: Automotive engineers often need to validate operation of a design on the bench and make sure a design is doing what it’s supposed to do. In other words, they need to “bring up” a design and characterize it to make sure it’s within spec. For this type of application, Tektronix oscilloscopes provide the tools needed to bring up the Automotive Ethernet PHY, for example. Automated measurements such as amplitude and time measurements offer a quick way to check signal quality while more advanced analysis tools such as eye diagrams, jitter profiles, and histograms help with more detailed evaluations.
Another common job facing automotive engineers is compliance testing to make sure ECUs and other components are truly interoperable. For this type of application, Tektronix provides proven, automated, standard tests and procedures designed to meet 100BASE-T1 standards as outlined in IEEE802.3bw, as well as the BroadR-Reach version as outlined by the OPEN Alliance. A key benefit of this type of compliance automation is that you don’t have to be an expert in the standard to perform compliance tests.
About the author:
Chris Godfrey is Market Development Manager at Tektronix-Danaher – www.tek.com