Question

What is responsible for most of the common-mode interfering signal?

(a) Preamplifier

(b) Notch Filter

(c) Power Line Hum

(d) Band Pass Filter

I got this question by my college professor while I was bunking the class.

Enquiry is from Ambulatory Monitoring Instruments topic in division Arrhythmia and Ambulatory Monitoring Instruments of Biomedical Instrumentation

Answer 1

Correct answer is (c) Power Line Hum

Best explanation: A sizable common-mode signal manages to pass through the input amplifier, a circumstance to be expected whenever electrodes spaced a few centimetres apart are attached to the human body in a hospital environment. Power line hum is responsible for most of the common-mode interfering signal. This is suppressed by a notch filter following the input amplifier.