GTU Electronics and Communication Engineering (Semester 5)
Electronics & Communication
May 2016
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary


Answer the following questions.
1 (a) (i) What is White Noise and what is its power spectral density.
2 M
1 (a) (ii) Define Image rejection.
2 M
1 (a) (iii) What is Carson's rule?
2 M
1 (a) (iv) What is diagonal clipping?
2 M
1 (a) (v) What is the figure of merit in DSB-SC and SSB-SC?
2 M
1 (b) Explain the Skin effect.
4 M

Find the Fourier Transform of following functions.
2 (a) (i) E-at u(t)
3 M
2 (a) (ii) \[ \begin {align*} X(t)=\text{rect }(t/\tau) = &\big \{ 1 \text{ for }-\tau/2 < \tau/2 \big \} \\ \ & \ \ \ 0 \ \ \ \text{ otehrwise} \end{align*} \]
4 M
Solve any one question from Q2(b) & Q2(c)
2 (b) A mixer stage has a noise figure of 20 dB, and this is preceded by an amplifier that has a noise figure of 9 dB and available power gain of 15dB. Calculate the overall noise figure referred to the input.
7 M
2 (c) Find overall noise figure of three stage cascaded amplifier, each stage having a power gain of 10 dB and noise figure of 4 dB.
7 M

Solve any two question from Q3(a), Q3(b) & Q3(c), Q3(d)
3 (a) Explain trapezoidal method of monitoring A.M waveform directly on an oscilloscope. Sketch trapezoidal pattern for 0 ≤ m ≤ 1.
7 M
3 (b) Explain Balanced modulator. Why a ring modulator is known as a double balanced modulator.
7 M
3 (c) Explain Phasing method for generation a SSBSC signal in detail.
7 M
3 (d) Explain the working of diode envelope detector and give the remedies for Negative Peak.
7 M

Solve any two question from Q4(a), Q4(b) & Q4(c), Q4(d)
4 (a) Discuss the Advantages & Disadvantages of FM Over AM.
7 M
4 (b) List all FM demodulators. Explain Foster - Seeley discriminator in detail.
7 M
4 (c) Explain a Varactor diode Modulator for FM Generation.
7 M
4 (d) Explain the importance of pre-emphasis and de-emphasis circuits. Why it is not useful in phase modulation but useful in frequency modulation?
7 M

Solve any two question from Q5(a), Q5(b) & Q5(c), Q5(d)
5 (a) Explain Superhetrodyne principal and superhetrodyne receiver.
7 M
5 (b) Explain automatic gain control in superhetrodyne receiver
7 M
5 (c) Define noise factor & derive Friis's formula.
7 M
5 (d) What is Ham radio? Discuss importance of Ham radio during natural calamities.
7 M



More question papers from Electronics & Communication
SPONSORED ADVERTISEMENTS