If you wear a pacemaker, you are probably already aware of the precautions you must take when you are in the vicinity of certain other devises. For those that may be unaware, there are many devices should never come into contact with the skin above the pacemaker, cordless telephones or electric razors for example. There are other devices which should never be within six inches of the pacemaker, Bluetooth emitters for example. And there are other devices that should never be used in the same room as a pacemaker patient, stun guns for example. Have you ever wondered why these restrictions exist?
When an electronic device operates, changing electrical currents and voltages cause electromagnetic interference ( EMI ). This EMI is transmitted into the space around the device, and can cause other proximate devices to malfunction, or to stop functioning all together. When an engineer designs a device, he must be acutely aware of how much EMI the device will transmit into the surrounding space, and he must also be aware of how much EMI can be present in his own space for his device to operate properly. The ability to both of these things, is called Electromagnetic Compatibility (EMC). In order to go to market and sell a device in the US, the FCC must test your device to confirm its emitted EMI is below the regulated threshold, and it also tests to make sure your device continues to operate in the presence of EMI at that threshold. Said in another way, they ensure your device is Electromagnetically Compliant. In other countries, the thresholds may be different, and the Testing Agency will be different, but compliance testing will be encountered in every country.
Since formal Compliance Testing by the FCC is a lengthy and expensive proposition, most engineers will try to monitor and test their Electromagnetic Compliance themselves before they contact the FCC for formal testing. This informal testing by the engineer is critical to ensure that the device design ultimately stays on time and on budget.
In general, if a device is not Electromagnetically Compliant, the FCC will not allow it to go to market. In some cases, however, the device is not compliant and can not be designed differently. If the device is considered medically essential, it will be allowed to go to market, with very clear operating restrictions. This is the case with Pacemakers.
If you want to learn more about the Formal FCC Compliance Testing, or if you want to learn more about how to informally test your device prior to formal testing, or if you want to learn how to design your circuits so that you will pass informal and formal testing, consider taking the upcoming ATI course EMC PCB Design and Integration. You can learn more about the course, and register for it here.
And, as always, you can look at our other classes, and our upcoming schedule of offerings at www.aticourses.com
Free Troubleshooting EMI workshop.
Identify, Characterize, and Prevent Electromagnetic Interference Problems
Hosted by Rohde & Schwarz
Join this highly focused free one-day seminar and learn how to uncover, characterize, and solve the most elusive EMI problems. Troubleshooting and localizing intermittent signals or multiple layers of broadband and narrowband signals can be frustrating even for the most seasoned EMC troubleshooter and RF engineer. We will discuss and demonstrate a number of test setups that can help the root causes of EMC test failures and then demonstrate how real-time analysis can literally make previously-hidden signals leap into plain view.
This seminar is intended for engineers and technicians involved in the development, troubleshooting, pre-compliance testing and certification of electronic products, systems and assemblies for EMC.