what is electro magnetic interfearence?

Question

i am an electronics engineer want to know the common effects of electro magnetism interfearence on Local area network

Answer 1

Wireless informatics systems such as a wireless local area network (WLAN) have the potential to reduce medical errors and improve the quality of healthcare delivery. With wireless informatics comes the concern that electromagnetic interference (EMI) from radio-frequency (RF) sources might cause critical-care medical devices to malfunction, threatening a patient’s life. To ensure patient safety, many hospitals ban wireless RF sources. To reap the benefits of wireless informatics, there is a need for EMI risk quantification. This paper examines various EMI risk models, and their applicability and limitations for WLAN planning in hospitals. A new EMI risk model quantifies EMI risk as a function of the separation distance between an RF source and a medical device. EMI risk models should become a part of a hospital’s WLAN planning and operation to maximize patient safety by ensuring electromagnetic compatibility.

Answer 2

EMI, is where there is a field generated with enough power to cause distortion in the Radio Frequency fields. Kind of the same Principle of EMP. Stong enough emp burst ruins anything wiht i nclose proximity to it and it no lnoger works until you replace teh fried parts. EMI is not quite that strong, but works on the same prinicples

Answer 3

According to wikipedia,

EMI is a radiation which is emitted by electrical circuits carrying rapidly changing signals, as a by-product of their normal operation, and which causes unwanted signals (interference or noise) to be induced in other circuits.

To reduce EMI and increase the efficiency of LAN cabling, shielding is used in making LAN cables.

From the following website you can read more about different CATegories of cabling

http://www.tsl.state.tx.us/ld/pubs/wireless/chapter6.html