Surely, you must have experienced something like this: When listening to a portable radio sitting right next to a computer or other appliance, you hear a humming noise in the background of the program you are listening to. When you move the portable radio away from it, the humming noise is gone. This is called an interaction.

An interaction could occur between any two or more electronic devices in the form of background noises like this example, line/white noise on TV reception or, even malfunction. Interaction occurs because the signal generated by one appliance is received by the other and causes reaction not intended.

Manufacturers design their products as to minimize such interaction. They should design their products: 1) to suppress noise emission levels and 2) to be resistant to neighboring noise. In most cases their effort is limited because they cannot assume every actual usage environment and budgetary reason. Maybe an interaction is not predictable (per their standard) or they cannot take a (costly) design margin. Or, instead of using more noise-resistant components (read: more expensive), use less-noise-resistant (less expensive) ones, etc, etc.

More interestingly, almost all electronics we use fall into FCC Part 15 category. What does that mean? The FCC statement often printed in user manuals or back covers of appliances state: "Operation is subject to the following two conditions: 1. This device may not cause harmful interference, and 2. This device must accept any interference received, including interference that may cause undesired operation." Now what do you do with them?

Installation for Home Electronics

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