Anna University Chennai B.E Electronics & Communication Engineering B.E/B.tech. Degree Examinations, May/June 2010, ECE, EC 1255-Measurements and Instrumentation Question paper

B.E/B.Tech. Degree Examinations, May/June 2010
Fourth Semester
Electronics and Communication Engineering
EC 1255 - Measurements And Instrumentation
(Regulations 2007)

Part A

1. Distinguish between accuracy and precision.
2. Compare Maxwell bridge with Hay's bridge.
3. State the advantages of digital storage oscilloscope.
4. A coil with a resistance of 8 ohm is connected in the direct connection mode of Q meter. Resonance occurs when the oscillator frequency is 1.5 MHz and the resonating capacitor is set at 60 pF. Calculate the % error introduced in the calculated value of Q by the 0.02 ohms insertion resistance.
5. List the applications of frequency synthesizer.
6. What is spectrum analysis?
7. A voltmeter uses 41/2 digit display. (a) Find its resolution. (b) How would 11.87 be displayed on a 10V range?
8. What are the advantages of Digital voltmeter?
9. What are the various devices connected on the GPIB?
Mention its function.
10.What are the electrical characteristics of GPIB?

PART B

11 (a) Mention about the static and dynamic characteristics of an instrument. Explain about them in detail.

(or)

(b) (i) The basic ac bridge consists of the following constants:
AB:R=400 ohms
BC:R=150 ohms in series with c=0.2 micro Farads
CD:unknown
DA:R=100 ohms in series with L=10mH.
Oscillator frequency is 1 KHz. Determine the constants of arm CD.
(ii) What is Wien's bridge? Derive the expression for the frequency. List its applications.

12 (a) (i) Draw and explain the various blocks of a sampling oscilloscope. List its advantages and applications.
(ii) Discuss in detail about the working principle of Q meter. What are the various sources of error in a Q meter?

(or)

(b) (i) Explain the working of a vector voltmeter with necessary block diagram. Mention its applications.
(ii) Discuss in detail about the various blocks of a genral purpose CRO.

13 (a) (i) What is harmonic distortion? Draw the block diagram of a heterodyne type spectrum analyzer. Mention about the information provided by a spectrum analyzer.

(or)

(b) (i) What is a wave analyzer? What is its uses? Explain the working of a frequency selective wave analyzer. Mention about its applications.
(ii) What are the various requirements of a signal generator? Discuss in detail about the working of a RF signal generator?

14 (a) (i) Explain the working of a succesive approximation type DVM.
(ii) Draw the block diagram of a Digital frequency counter and explain the working.

(or)

(b) (i) What is the use of period measurement? Draw the block schematic of a period measurement set up and explain.
(ii) Give the specifications of a digital multimeter. Draw the general block schematic of a digtal multimeter and explain.

15 (a) (i) What are the various elements of a digital data acquisition system? Explaim in detail about each element.
(ii) What is the need for interfacing of transducers? What are the techniques used? Explain.

(or)

(b) (i) What is the need for a computer controlled test system? Discuss in detail about the IEEE 488 standards and the bus structures.
(ii) Mention about the advantages of fiber optic measurements for power. Discuss about the system loss and apllications of fiber optics in measurements.