Biomedical Instrumentation Questions and Answers – Biomedical Signal Analysis and Processing Techniques

This set of Biomedical Instrumentation Multiple Choice Questions & Answers (MCQs) focuses on “Biomedical Signal Analysis and Processing Techniques”.

1. Which of the following statement is true for an instrumentational amplifier?
a) the input resistance of both the inputs is very high and does not change as the gain is varied
b) the input resistance of both the inputs is very low and does not change as the gain is varied
c) the input resistance of both the inputs is very high and does change as the gain is varied
d) the input resistance of both the inputs is very low and does change as the gain is varied

Explanation: The input resistance of both the inputs is very high and does not change as the gain is varied in and instrumentational amplifier. Voltage gain from differential input (V1–V2) to single ended output, is set by one resistor. V0 does not depend on common-mode voltage, but only on their difference.

2. Which of the following is not the property of the instrumentational amplifier?
a) Extremely high input impedance
b) Low bias and offset currents
c) High slew rate
d) Very low CMRR

Explanation: Instrumentational amplifiers have very high CMRR. The instrumentation amplifier offers the following advantages for its applications in the biomedical field. Some of them are like extremely high input impedance, low bias and offset currents, high slew rate.

3. CMRR is measured in ___________
a) v/s
b) dB
c) dB/s
d) dB/ms

Explanation: CMRR is an important specification referred to the differential amplifier and is normally expressed as decibels. The ability of the amplifier to reject common voltages on its two input leads is known as common-mode rejection. It is specified as the ratio of common-mode input to differential input to elicit the same response.

4. The carrier amplifier consists of an oscillator and a capacitance coupled amplifier.
a) True
b) False

Explanation: The carrier amplifier consists of an oscillator and a capacitance coupled amplifier. The oscillator is used to energize the transducer with an alternating carrier voltage. The transducers, which require ac excitation, are those whose impedance is not purely resistive.

5. Electromagnetic coupling cannot be reduced by ___________
a) shielding
b) wire twisting
c) multiple grounding
d) common grounding

Explanation: 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. Thus, the electromagnetic coupling is reduced by shielding, wire twisting and proper grounding which provide a balanced signal pair with satisfactory noise rejection characteristics.
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6. Which on the following is not a type of isolation amplifier?
a) capactively coupled isolation amplifiers
b) optically isolated isolation amplifiers
c) resistive coupled isolation amplifiers
d) transformer type isolation amplifiers

Explanation: There is nothing such as the resistive coupled isolation amplifiers. All the other three types are in common use, though the transformer isolation amplifier is more popular. Opto-coupled amplifier uses a minimum number of components and is cost effective, followed by the transformer coupled amplifier. The capacitor coupled amplifier is the most expensive.

7. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.
a) True
b) False

Explanation: The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier. Three methods are used in the design of isolation amplifiers: (i) transformer isolation (ii) optical isolation (iii) capacitive isolation. Isolation amplifiers are commonly used for providing protection against leakage currents.

8. _________ are commonly used for providing protection against leakage currents.
a) Isolation amplifiers
b) Differential amplifiers
c) Instrumentational amplifiers
d) Inverting amplifiers

Explanation: Isolation amplifiers are commonly used for providing protection against leakage currents. They break the ohmic continuity of electric signals between the input and output of the amplifier. The isolation includes different supply voltage sources and different grounds on each side of the isolation barrier.

Sanfoundry Global Education & Learning Series – Biomedical Instrumentation.