A comprehensive test solution helps perform precise timing measurements on in-vehicle networks with nanosecond accuracy for Layers 1-3. The test setup provides a tailored oscilloscope solution based on the R&S RTO, while TSN Systems contributes TSN Box, a hardware interface to the network and TSN Tools, a measurement and analysis software.
The test setup monitors an automotive Ethernet 100BASE-T1 communication link consisting of TSN Box 3.0 acting as talker, listener and test access point (TAP) device. The TSN Box 3.0 TAP device provides information to a PC with TSN Tools based on Layers 2 and 3. The TAP introduced 2x PHY delay for 100BASE-T1 at around 1.5 μs ±10 nsec. The R&S RTO oscilloscope was used along with the R&S RTx-K35 bus measurements statistics option to measure and verify this timing accuracy in the physical layer of the automotive Ethernet signal (Layer 1). The mean time delay was measured to be precisely 1.5 μsec with a max deviation of ±10.2 nsec. In addition, the Qbv traffic (IEEE802.1) was generated by the TSN Box 3.0 with 500 μsec cycle time resulting in a jitter ranging from 8 to 20 nsec, which was verified by both the TSN Tools and the R&S RTO.
The combination of TSN Tools and TSN Box provides a broad range of functions to address validation and testing for time sensitive automotive Ethernet. While TSN Tools is a PC-based analysis software performing visualization and deep detail analysis, the TSN Box serves as a precise interface to the link. Based on its
configuration, it can act as a generic TSN Talker/Listener device with nanosecond precision. The TAP can transparently synchronize itself to the gPTP master in the network. This allows powerful applications that need correlation between payload time stamps and TAP time.
The R&S RTx-K35 software option for the R&S RTO oscilloscope enables high precision latency measurements, for example, monitoring the communication between two devices for a long period, and provides statistics on error rates as well as frame timing on the packets. The R&S RT-ZF7 test fixture acts as the link in the middle and allows the full monitoring between the transmitter and receiver device in both directions using the oscilloscope.
In combination with the suitable decoding option, the 100BASE-T1 time data can be measured frame-to-frame, and engineers can get full bus error statistics such as frame error rate and rate of consecutive errors. Moreover, they can perform precise timing measurements for all automotive serial bus protocols such as automotive Ethernet, CAN, CAN-FD, LIN, I2C and more.
For further information on the Rohde & Schwarz solutions for automotive Ethernet and other bus systems, visit: www.rohde-schwarz.com/automotive/ethernet
For more information on TSN System’s automotive solutions, visit: https://tsn.systems/