Automotive Ethernet Compliance: Tests in Detail (Part II)

Figure 1: Testing transmitter timing master jitter
entails creating a track of TIE measurements

We've begun our deep dive into the subject of Automotive Ethernet compliance testing. In our last post, we covered the first two of seven tests: maximum transmitter output droop and transmitter clock frequency. Let's now look at transmitter timing jitter in master and slave modes.

Automotive Ethernet Compliance: Tests in Detail (Part I)

Figure 1: Maximum transmitter output droop should not
exceed the specified maximum of 45%

We've looked in past posts at the basics of Automotive Ethernet compliance test, the five test modes, and an overview of the test setup. Now it's time to begin examining the physical-layer electrical tests in detail. As we've mentioned, there are a total of seven of these tests (six for BroadR-Reach and 100Base-T1 and one for the latter only).

Automotive Ethernet Compliance: Test Setup Overview

Figure 1: Typical test setup for Automotive Ethernet
PMA compliance test

Our last post, an overview of the five test modes for Automotive Ethernet electrical compliance testing, prepared us for a deeper look at the compliance tests themselves. But before diving into details on the differential electrical compliance tests for Automotive Ethernet, be it BroadR-Reach or 100Base-T1, it might be helpful to take a look at the setup for this endeavor.

Automotive Ethernet Compliance: The Five Test Modes

Figure 1:Automotive Ethernet electrical compliance test
is defined at the connector of the transmitter

Following up on our introduction to Automotive Ethernet compliance testing, let's move on to an overview of the five test modes that comprise the compliance test suite for the 100Base-T1 protocol. The test modes allow for a common pattern to test stressful conditions across all devices. Testing in this fashion offers the best possible odds for achieving true interoperability.

Introduction to Automotive Ethernet Compliance Testing

As with most any networking scheme, Automotive Ethernet is subject to standardization to ensure that the various components of a given system reliably pass signals among themselves. Where there is a standard for a protocol, there must also be testing for compliance with that standard. This will be the first in a series of posts detailing compliance test of the Physical Media Attachment (PMA) aspect of the Automotive Ethernet standard.

Back to Basics: Metrology

Some sciences are more obscure than others; these may be of interest and importance to relatively few. The term “metrology” may leave even some science geeks scratching their heads, but for those in the test and measurement arena, metrology is an extremely critical area of scientific endeavor.

The Periodic Table of Oscilloscope Tools: Document

Oscilloscope users can find themselves managing a lot of detail in the course of driving their instruments. They need to keep track of instrument setups. They have to know standards-based compliance test routines backward and forward. Often, the need arises to remotely control the oscilloscope, interface it with other applications, and export/import acquisition data. And, importantly, the oscilloscope has to aid, and not hinder, collaboration with other members of the engineering team(s).

And thus we arrive at the end of our survey of the Periodic Table of Oscilloscope Tools with the Document portion.

• Hardcopy: Use the oscilloscope's Print button to pre-define a documentation action and execute that action with the press of one button. Select to create a file of a screen image in a variety of formats; send an email with an attached screen image; copy data to a clipboard; print a document; or save the waveform data, screen images, panel setups, and the end user's annotations as a LabNotebook (see below).