Keysight Technologies 3000X Series Oscilloscopes in the Automotive Industry

In order to improve system communication efficiency and reduce costs, all current automotive designs use a large number of serial bus communication protocols. I2C and SPI protocols are usually used in chip-to-chip communication of electronic control units (ECUs). For long-distance serial communication and control between various automotive subsystems (such as comfort control systems, anti-theft locks, transmission systems, and engine controls), CAN, LIN, and FlexRay protocols are common serial bus applications in today's automotive industry.

Keysight Technologies 3000 X-Series oscilloscopes simultaneously capture and decode CAN and FlexRay buses. At the bottom of the display are time-correlated decode traces for each bus, below the captured physical layer waveforms. The top half of the oscilloscope display shows an industry-first time-interleaved "lister" display, sometimes called an event table. This data format is closer to that of a traditional protocol analyzer.

Keysight Technologies InfiniiVision Series oscilloscopes feature hardware decoding, while other oscilloscopes on the market today use software decoding. Software decoding techniques have a slow update rate, especially when using deep memory. Hardware decoding provides real-time updates of serial bus activity without slowing down, even with deep memory. This increases the chances of the oscilloscope capturing random and infrequent communication errors. In addition to providing decoded words that are time-correlated with the captured waveform, another very effective tool is eye-diagram mask testing, which verifies the signal integrity of the high-speed FlexRay bus. Eye-diagram testing is widely used in today's serial bus applications. Basically, the eye diagram is a superposition of all the bits captured by the oscilloscope, showing whether the bits are valid or not. It provides a composite picture that describes the overall quality of the system's physical layer characteristics, including amplitude variations due to transmission line effects, reflections, system noise, overshoot, ringing, signal edge timing, and jitter.

The trigger reference for the TP4 mask test is based on each Byte Start Sequence (BSS) event. This is the same reference signal that the FlexRay receiver uses to resynchronize and recover the clock used to sample the received data. Keysight's InfiniiVision Series oscilloscopes use a unique repetitive hardware clock recovery technique to capture and overlay every bit of every byte in a synchronized FlexRay system. Note that the oscilloscope can also "filter" the capture and overlay of FlexRay eye diagram data based on a special frame ID.

If you need to buy a new oscilloscope to support automotive serial bus applications, you can choose Keysight's 3000 X-Series oscilloscopes covering 100 to 500 MHz bandwidth. These oscilloscopes come standard with a three-year warranty and an industry-leading two-year recommended calibration cycle.

When purchased with the DSOX3AUTO option, the oscilloscope provides CAN and LIN serial triggering and decoding capabilities. When purchased with the DSOX3FLEX option, the oscilloscope provides FlexRay serial triggering and decoding capabilities. When purchased with the DSOX3MASK mask test option, the oscilloscope can perform eye-diagram mask testing on FlexRay buses. Various FlexRay mask files based on baud rate and test planes (TP#) are available for free download. When probing differential CAN buses, Keysight recommends using the N2791A 25-MHz differential active probe