Electromagnetic interference or EMI is any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electronic or electrical equipment. It can be induced intentionally, as in some forms of electronic warfare, or unintentionally, as a result of spurious emissions and responses, intermodulation[?] products, and the like. It is also known as radio frequencyinterference.
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An early example of a DRM system is the Content Scrambling System (CSS) employed by the DVD Consortium[?] on movie ...