For years, oscilloscopes have been the primary measurement tools used to verify the signal integrity of the CAN bus physical layer. With the new CAN eye-diagram mask test capability in Agilent’s 3000 X-Series oscilloscopes, engineers now have the ability to perform a composite signal-integrity measurement of their CAN buses in one easy measurement.
Eye-diagram mask testing is one of the most important ways designers can measure the overall signal quality of their serial bus networks. The CAN eye-diagram test randomly captures and overlays every differential bit of every CAN frame based on a unique clock-recovery algorithm that emulates worst-case CAN receiver hard synchronization, resynchronization and sampling. The result is a single measurement that provides insight into the overall signal integrity of the CAN’s physical layer to show worst-case timing and worst-case vertical amplitude variations. Overlaid bits are then continually compared against a six-point polygon-shaped pass/fail mask limit, which is based on CAN physical-layer specifications.
Controller Area Networks are based on an asynchronous event-driven architecture, so physical delays are the dominant contributor of timing uncertainty. The longer the Controller Area Network, the longer the delays. Agilent’s new CAN eye-diagram mask testing capability clearly detects and shows these worst-case network delays.
Information about the DSOX3AUTO option is available.
The DSOX3AUTO CAN/LIN trigger and decode option and the DSOX3MASK mask-test option (both are required for CAN eye-diagram mask testing) are priced at $729 each. The entry-level price of an Agilent InfiniiVision 3000 X-Series oscilloscope with these options is $4,324. Customers who already own an Agilent 3000 X-Series oscilloscope with the DSOX3AUTO and DSOX3MASK options can upgrade their scopes with the latest firmware to enable CAN eye-diagram mask testing at no charge.
Agilent also provides a broad range of specific mask-test files based on differential probing polarity, baud rate and network length. These mask-test files can be downloaded at no charge.