Problem 2 AConsider a cellular system of hexagonal structure. It is assumed that all the base stations transmit with the same power and the path loss follow the break-point model with exponent 4. The required S/I (signal power to interference power ratio) is 12dB. The fading margin is 10dB. What is the minimum cluster size?

Q7. Figure Q7 shows a modulated waveform v(t) in millivolts as a function of time t in nanoseconds. 1.5 1.0 0.5 - 0.0 -0.5 -1.0 -1.5 100 200 300 400 500 t/ns Figure Q7: Modulated waveform (a) Describe the modulation scheme. (b) What are the values of the carrier frequency and the modulation frequency? (c) What is the value of the modulation index? (d) What is the transmission efficiency (ratio of modulated to total power) in this example? (e) Sketch the spectrum of this modulated waveform indicating the relative magnitudes of the various spectral components. (f) Demodulation of this type of waveform is usually performed with an envelope detector. Describe the function of an envelope detector and sketch an example circuit. (g) What requirements on the values of the components of your envelope detector circuit are there for the successful demodulation of the given waveform? (h) Keeping the same carrier wave, the modulating wave in this example is substituted with a square wave of 50%…

Q6. Figure Q6 shows the line spectrum of a modulated signal (all components are positive and real). 3 1 232 234 236 238 frequency/kHz Figure Q6: Line spectrum of a modulated signal (a) Describe the modulation scheme. (b) What are the values of the carrier frequency, modulation frequency and the modulation index? (c) What is the transmission efficiency (ratio of modulated to total power) in this example? (d) The reception of this signal is undertaken with a superheterodyne detector using an intermediate frequency of 110 kHz. What is the appropriate local oscillator frequency? (e) Demodulation of this type of signal is usually accomplished using an envelope detector. Describe the principles of operation of an envelope detector and sketch an example circuit. (f) What considerations should be made about the component values in the design of an envelope detector in order to demodulate the signal after shifting to the intermediate frequency? Relative unitsS