Common errors have been seen in EMI testing over a great number of years and the guidelines used for successful EMI Testing GENERAL ERRORS APPLICABLE TO MOST TEST Inadequate testing methods and flagging all possible failures. Reference 3 9.4.11.2.1 details the correct method of functional testing the Equipment Under Test. The shielding of power cables must remain … [Read more...]
Fundamental Oscilloscope Probes
As electronics have become more advanced, so has the equipment used to measure their signal behavior and system performance. In the realm of EMC compliance, oscilloscopes are one of the important tools used to measure signals, hunt down noise sources, and identify time-domain measurements that may contribute to radiated or conducted emissions. Without a properly selected probe, … [Read more...]
Radiated Emissions Testing
INTRODUCTION Radiated emissions testing is only one part of emissions testing. CISPR 32, the document that lays out limits and methods of measurement for emissions (radiated and conducted) for Information Technology Equipment (ITE), broadcast receivers and multimedia equipment is 120 pages in length. ANSI C63.4 deals with only the testing part (limits are contained in a … [Read more...]
New Touchless Hidden Switch is Concealed Behind Surface
Santa Rosa, California, August 10th, 2023 – SCHURTER introduces the innovative THS switch series with optical sensor technology that can be concealed behind any surface without the need for mounting holes. A small opening in the user interface is all that is needed to allow the ToF sensor to actuate. Equipment and appliances used in public areas has created demand for … [Read more...]
Summary of Commercial EMC Tests
Introduction Commercial EMC tests cover a wide range of products. These include the obvious ones like computers and their peripherals but also cover household appliances, electric tools, and a wide variety of other products. While the standards, including limits and test methods, may differ, all EMC test standards have a few things in common. The most basic are the limits for … [Read more...]
Protecting RF, Receiver, Analog and Control Line Input Circuits Against The RTCA DO-160 Pin Injection Lightning Test
ABSTRACT Circuits are described that effectively protect RF, receiver, analog, and control line input circuits from three types of transient injection, described in DO-160, directly into the input pin of the connector. The goal was to achieve a circuit which would not adversely affect the performance of the RF circuit over an input frequency range of 20MHz to above 1GHz … [Read more...]
The Vital Role Of Simulation For Virtual EMI And EMC Test Environments
Before deploying microwave and millimeter-wave devices and systems within 5G, the Internet of Things (IoT), and high-speed wireless communication, it is essential to predict their performance. This need has increased the demand for virtual test platforms through simulation software. High carrier and system bus frequencies are necessary for high-data-rate communication … [Read more...]
Knee Frequency is A Misleading Bandwidth Metric
INTRODUCTION There is a transmission line critical length rule that is often used in high-speed PCB design by novice engineers. This rule should not be used and is not appropriate for high-speed PCBs. The bandwidth limit of a digital signal or a high-speed digital channel is often used in certain calculations to get estimates of channel behavior. For example, the knee … [Read more...]
Stop Using the Critical Length Rule in High Speed PCB Design
The PCB world is in flux and an inrush of new designers is appearing on the horizon. Unfortunately, marketing material from manufacturers and CAD companies continues to spread outdated design guidelines that are easily misapplied, or they are simply wrong. One of these design rules that appears to be endemic is the critical length rule for transmission lines. This rule is used … [Read more...]
Placing a Metal Plate in Front of a EUT May Not Be Enough to Solve Radiated Emissions Exceedances or Radiated Susceptibility Failures
EXAMPLE OF AN EUT WHICH HAS FAILED RADIATED SUSCEPTIBILITY As described in reference 1, the EUT was exposed to a radiated immunity test at a level of 20V/m. The side which contained a vertical metal plate, with an approximately 0.3m x 0.3m dimension and which was electrically isolated from a metal baseplate failed at 12V/m and 300MHz. On the other sides of the EUT, … [Read more...]
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