Grounding: electromagnetic interference

Biotelemetry is one way to provide this kind of isolation. In conjunction with battery-powered amplifiers, biotelemetry can be a very effective way to reduce electromagnetic interference in biopotential recordings since it can be isolated from ground reference. This is depicted in Fig. 17.30. Here, the isolated system reference is shown by the triangle symbol rather than the segmented lines of earth ground. 

Electronic and PE logic solvers typically are more sensitive to electrical noise (e.g., radio frequency interference or electromagnetic interference), consequently, shielding, good wiring practices, and proper grounding should be utilized. 

Isolated ground (IG) receptacles, which are a version of single-point grounding, are permitted by the NEC where required for the reduction of electrical noise (electromagnetic interference) on grounding circuits. Proper appHcation of IG receptacles is very important, and the specific NEC requirements must be followed. 

The requirement to maintain electrical continuity in grounding and electromagnetic interference (EMI) shielding requires that corrosion in the contact areas be avoided. Galvanic corrosion, where dissimilar metals must be bonded, can lead to an increase in electrical resistance and loss in grounding. The same effect can occur with thermal contacts with the additional effect of higher temperatures. 

Radome Also called radiation dome. It is a cover for a microwave antenna used to protect the antenna from the environment on the ground, underwater, and in the air (aircraft nose cone, etc.). The dome is basically transparent to electromagnetic radiation and structurally strong. Different materials have been used such as wood, rubber-coated air-supported fabric, etc. The most popular is the use of glass fiber-TS polyester RPs. The shape of the dome, that is usually spherical, is designed not to interfere with the radiation. 

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