Question

Reduction in electromagnetic coupling is achieved by _____

(a) shielding

(b) common grounding

(c) multiple grounding

(d) wire twisting

The question was asked in class test.

This intriguing question comes from Single Channel Telemetry System topic in division Biomedical Telemetry of Biomedical Instrumentation

Answer 1

Correct choice is (c) multiple grounding

For explanation: Electromagnetic coupling is reduced by shielding, wire twisting and proper grounding which provide a balanced signal pair with satisfactory noise rejection characteristics. Having multiple grounds in a single circuit increases the electromagnetic coupling effect by producing ground loop which may generate so much noise that it may completely obscure the useful signal.