Electronic Instruments and Measurements - May 2012

Electronics & Telecomm. (Semester 3)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks.

Attempt any FOUR from the following

1 (a) Why is delay line used in the vertical section of Oscilloscope(5 marks) 1 (b) What is universal counter?(5 marks) 1 (c) Explain capacitive sensors(5 marks) 1 (d) Explain various sources of errors in measurement system?(5 marks) 1 (e) Explain the significance of 3-1/2 and 4-1/2 digit displays 3-1/2 Digit Display:(5 marks) 2 (a) Explain the Elements of digital FFT analyzer with a suitable block diagram.(10 marks) 2 (b) What is the basic principle of ADC? Explain the operation of successive approximation type of ADC.(10 marks) 3 (a) Explain the principle of working of LVDT. How do stray magnetic fields effect the performance and how it can be protected.(10 marks) 3 (b) Draw and explain the block diagram of general purpose CRO.(10 marks) 4 (a) Derive the expression for vertical deflection of electron beam in CRT.What is the minimum distance that will allow full deflection of 4cm at oscilloscope screen with deflection factor of 100V/cm and with accelerating potential of 2k.(10 marks) 4 (b) Explain PAM telemetry system.(10 marks) 5 (a) With block diagram explain the elements of network analyser with its application.(10 marks) 5 (b) Draw and explain the block diagram of DSO.Describe the various modes of operations.(10 marks) 6 (a) Explain the need of data transmission and telemetry. What are the different modulation methods used in RF telemetry system.(10 marks) 6 (b) Write a note on automatic test equipment. A coil with a resistance of 5ohm is connected directly to test terminals of Q-meter, for a 130 pf capacitance of tuning capacitor, resonance is obtained at oscillator frequency of 1MHz.Calculate % error introduced in calculated value of Q by 0.01 insertion resistance.(10 marks) 7 (a) Draw and explain true RMS voltmeter with thermocouple. Why there is error in reading a voltmeter calibrated to RMS values when it is used into read signals other then sine wave.(10 marks) 7 (b) Explain briefly the different pulse modulation techniques.(10 marks)