Biomedical Instrumentation Questions and Answers – General Considerations for Signal Conditioners

This set of Biomedical Instrumentation Questions and Answers for Experienced people focuses on “General Considerations for Signal Conditioners”.

1. The filter used to reject the 50Hz noise picked up from power lines or machinery is called?
a) band reject filter
b) band stop filter
c) notch filter
d) all reject filter
View Answer

Answer: c
Explanation: Such filters are called notch filters. Almost all measuring and recording applications are subjected to some degree of 50Hz noise picked up from the power lines or machinery. Therefore, most signal conditioners include low pass filter designed specifically to provide maximum rejection of 50 Hz noise.

2. Devices that pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique are called?
a) filters
b) rectifiers
c) bridges
d) isolaters
View Answer

Answer: d
Explanation: Such devices are called isolaters. Improper grounding of the system is one of the most common causes of measurement problem and noise. Signal conditioners with isolation can prevent these problems. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.

3. Which of the following technique is not employed in isolation devices?
a) resistance
b) optical
c) inductance
d) capacitance
View Answer

Answer: a
Explanation: Resistance technique is not employed in making isolation devices. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.
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4. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages.
a) True
b) False
View Answer

Answer: a
Explanation: It is true. Besides breaking ground loops, isolation blocks high voltage surges and rejects high common mode voltages. The isolation devices pass the signal from its source to the measurement device without a physical or galvanic connection by using transformer, optical or capacitive coupling technique.

5. Strain gauges are resistance devices in a Wheat stone bridge configuration _________
a) which does not require bridge completion circuitry and an excitation source
b) which requires bridge completion circuitry and an excitation source
c) which neither requires bridge completion circuitry nor an excitation source
d) which requires bridge completion circuitry but does not an excitation source
View Answer

Answer: b
Explanation: Strain gauges are resistance devices in a Wheat stone bridge configuration which requires bridge completion circuitry and an excitation source. These devices require external voltage or current excitation. Signal conditioning part of the measurement system usually provides the excitation signals.
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6. Which of the following voltage regulator IC gives a variable positive voltage?
a) LM317
b) LM337
c) 7805
d) 7812
View Answer

Answer: a
Explanation: LM317 is a variable positive voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from 1.25V- 30V ideally. LM337 is a variable negative voltage regulator IC. 7805 and 7812 are fixed voltage regulator IC that give output voltage as 5V and 12V respectively.

7. ________ IC is a variable negative voltage regulator.
a) 7912
b) 7905
c) LM337
d) LM317
View Answer

Answer: c
Explanation: LM337 is a variable negative voltage regulator IC. It is capable of drawing current up to 1.5A and voltage range from (-1.25V) – (-30V) ideally. LM317 is a variable positive voltage regulator IC. 7905 and 7912 are fixed voltage regulator IC that give output voltage as -5V and -12V respectively.
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8. Digital filters are sensitive to temperature as compared with analog filters.
a) True
b) False
View Answer

Answer: b
Explanation: False. Digital filters are insensitive to temperature as compared with analog filters. They are also insensitive to ageing, voltage drift and external interference as compared to analog filters. Their response is completely reproducible and predictable, and software simulations can exactly reflect product performance.

9. Signal conditioning is not of much importance in the measuring and recording system.
a) True
b) False
View Answer

Answer: b
Explanation: Signal conditioning is of great importance in measuring and recording system. They determine the range, accuracy and resolution of the system. Signal conditioning includes either hardware based or software based linearization routines for this purpose.
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Sanfoundry Global Education & Learning Series – Biomedical Instrumentation.

To practice all areas of Biomedical Instrumentation for Experienced people, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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