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13 September 2016

Why IEEE's Pulse Definitions and ESD Pulses Don't Mix

The IEEE's pulse definitions, which don't fit the bill for measuring ESD pulses
Figure 1: The IEEE's pulse definitions, which don't fit
the bill for measuring ESD pulses
The IEEE's pulse definitions, found in the organization's Std 181-2011 that covers transitions, pulses, and related waveforms, set the bar for how pulse measurements are determined. These definitions, which are in the DNA of all oscilloscopes, are just the thing for measuring repetitive pulses such as clock signals but not so much for ESD/EMC measurement requirements. In this post, we'll discuss why that is and what you should do differently for measuring ESD pulses.

30 August 2016

Making EMC/ESD Pulse Measurements

Four quadrants of EMC/ESD testing
Figure 1: Oscilloscopes are used for
testing in the green-shaded boxes
There are many circumstances in which electromagnetic compatibility (EMC) and electrostatic discharge (ESD) testing are a fact of life. Many countries have adopted IEC international standards that dictate certain levels of immunity, as have the automotive, medical, military, and aerospace industries. In this post, we'll begin looking at how oscilloscopes figure into tests for both radiated and conducted EMC/ESD immunity.

15 July 2016

Are You Ready for Bluetooth 5?

Bluetooth logo
The Bluetooth Special Interest Group, which is the body that oversees the protocol's specification, doesn't stand still but rather continues to develop and improve Bluetooth technology. With an eye toward building an accessible and interoperable Internet of Things (IoT), the next version of the Bluetooth specification—Bluetooth 5—is slated to appear by early in 2017 and as soon as this fall.

08 July 2016

The Power Delivery 2.0 Protocol in Action

A high-level view of a PD 2.0 power  contract negotiation
Figure 1: A high-level view of a PD 2.0 power
contract negotiation
The Power Delivery 2.0 protocol brings a boatload of intelligence to the process of establishing power relationships between partners in a USB Type-C link. In previous posts, we've examined the basics of the two standards, the workings of USB Type-C cable detection, how dual-role port devices are handled, and PD 2.0 messaging. Next, let's look at PD 2.0 in action by deconstructing the initialization of a Google Chromebook laptop, which was one of the first Power Delivery devices on the market.

14 June 2016

Just the FAQs: Waveform Averaging

The upper grid displays raw samples directly from the ADC; the lower grid displays the average of 1000  acquisitions.
Figure 1: The upper grid displays raw samples directly from
the ADC; the lower grid displays the average of 1000
acquisitions.
If you've poked around the Teledyne LeCroy website, perhaps you've run across the extensive (and growing) collection of test-related tidbits we call our FAQ Knowledgebase. To highlight some of these helpful hints for making better use of your oscilloscopes, protocol analyzers, network analyzers, etc., we'll post some here on the Test Happens blog from time to time.

02 June 2016

USB Type-C and Dual-Role Port Devices

This protocol analyzer capture shows how a DRP alternates between voltage source and sink until it sees one  or the other at the far end of a link
Figure 1: This protocol analyzer capture
shows how a DRP alternates between
voltage source and sink until it sees one
or the other at the far end of a link
At this juncture in our ongoing series of posts about USB Type-C and power delivery, it's time to acknowledge that some Type-C devices are not strictly a power source or sink. Some are called out in the Power Delivery 2.0 specification as dual-role port (DRP) devices that may act as either a source or sink for power. Note that unlike in the original OTG spec, this applies only to a port's power role, not to being a USB host or connected device.

19 May 2016

USB Type-C and Power Delivery Messaging

Power Delivery messaging comprises two types: Control and Data
Figure 1: Power Delivery messaging comprises two types:
Control and Data
Continuing our review of USB Type-C and the associated Power Delivery 2.0 (PD) specification, let's now turn to PD message types. Whereas USB was originally conceived as primarily a serial-data interface with limited power-delivery capabilities, the proliferation of power-hungry mobile devices has forced a rethinking of that conception. With PD 2.0 came a much more flexible, and capable, power-delivery functionality for USB. PD messaging is a critical component in this regard.