Section A
Q1.
(a) An angle-modulated signal has the form u(t) = 100 cos[2π fc t + 4 sin 2000π t] where fc = MHz.
(i) Determine the average transmitted power. (ii) Determine the peak phase and frequency deviation. (iii) Is this FM or PM signal? Explain. 4+4+2=10
(b) A unity feedback control system has the open-loop transfer function G(s) = (K)/(s(Ts + 1)) The system is critically damped and the steady-state error is 0.5 when unit ramp input is applied. Find out the natural frequency of the system.
(c) With respect to cache memory organization, describe the importance of cache addressing models, considering physical address cache, virtual address cache and aliasing problem. Write a block schematic depicting memory hierarchy for a shared memory multiprocessor. 5+5=10
(d) For an air-filled coaxial transmission line, the outer radius of the inner conductor is 1 mm and the inner radius of the outer conductor is 4 mm. The outer conductor thickness is 0.6 mm and all conductors have conductivity σ = 1.6 × 107 S/m. Find the inductance L and capacitance C per unit length. What will be the resistance per unit length at an operating frequency of 2.5 GHz? The value of \varepsilon0 = 8.854 × 10-12 F/m and μ_0 = 4π × 10-7 H/m.
(e) Design 4-to-1 multiplexer using domino logic.
(f) A silicon p-i-n photodiode in an optical receiver receives a peak optical power at 1300 nm. The diode has a quantum efficiency of 50% and delivers electrical power to a load of 8 \text k\Omega. If the diode receives a peak power of -30 dBm, calculate the thermal noise and shot noise if the bandwidth of operation is 8 MHz. The dark current value = nA. [e = 1.6×10-19 \text C, h = 6.63×10-34 \text J-s, c = 3×108 \text m/s, k_{\textB} = 1.38×10-23 \text J/K] SGSE-T-ETE/72 2
