STUPIDSID
1 (a)
What is an unilateral figure of merit of an amplifier?
5 M
1 (b)
Define signal to noise ratio and noise figure with help of a noisy network.
5 M
1 (c)
Define stability. List the various criteria for stability.
5 M
1 (d)
Explain the terms conversion loss and isolation with reference to mixer.
5 M
2 (a)
For an ideal transformer with turns ratio n= -1/n2. Prove that the scattering matrix is: \[ S=\begin{bmatrix}
\frac {n^2-1}{n^2+1} & \frac {2n}{n^2 +1} \\ \frac {2n}{n^2+1}
& \frac{1-n^2}{n^2+1}
\end{bmatrix} \]
10 M
2 (b)
Discuss amplifier linearization methods.
10 M
3
A GaAs FET has the following S-parameter and noise parameters at 1.0 GHz (Z0=50 Ω) S11=0.61<-155°, S12=0, S21=5.0 < 180°, S22=0.51 <-20°, Fmin=3dB, Γopt=0.45<180°, RN=4Ω. Design a Low noise amplifier for a noise figure of 3.5 dB and power gain of 16 dB.
20 M
4 (a)
Derive the transducer power gain as \[ G_T = \dfrac {P_L}{P_{avg}} = \dfrac{|S_{21}|^2 (1-|\Gamma_S|^2)(1-|\Gamma_L|^2)}{|1-\Gamma_S\Gamma_{in}|^2 |1-S_{22}\Gamma_L|^2} \]
10 M
4 (b)
Design a transistor oscillator at 4 GHz using GaAs FET in common gate configuration with 5nH inductor in series. Common gate configuration S-parameter are S11=2.18<-35°, S21=2.75<96°, S12=1.26<18°, S22=0.52<155°, Select ΓT so that Γin>1.
10 M
5 (a)
Explain using suitable diagrams two methods of designing broadband amplifier.
10 M
5 (b)
Discuss generator tuning networks for microwave oscillators.
10 M
6 (a)
Explain with IC=30mA and VCC=10 V is operated at a frequency of 1.0 GHz in a 50 Ω system.
S11=0.73 < 175°, S22=0.21 <-89°, S12=0.0, S21=4.45<65°. Is the transistor unconditionally stable? If yes, calculate the optimum terminations. GSmax, GLmax and GTUmax.
S11=0.73 < 175°, S22=0.21 <-89°, S12=0.0, S21=4.45<65°. Is the transistor unconditionally stable? If yes, calculate the optimum terminations. GSmax, GLmax and GTUmax.
10 M
Write short note on.
7 (a)
Noise figure test equipment.
5 M
7 (b)
Comparison of microwave amplifier and oscillator.
5 M
7 (c)
1dB compression point
5 M
7 (d)
Properties of scattering matrix.
5 M
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