3. (a) Draw the circuit diagram of a 4-bit pseudo-random binary sequence (PRBS) generator. (i) Discuss briefly the operation of the circuit. (ii) Show how the output from the PRBS generator may be used to convert a digitized speech signal to a Direct Sequence Spread Spectrum (DSSS) output. Page 4 of 5 [10 marks] Programme Code: TU821 Module Code: COMM2603 CRN: 15324 (b) Considering the PRBS generator of Question 3(a) (1) What would be the first 16 serial bits at the output of this system? Illustrate how you got your answer. (ii) How many bits occur at the output of the system before the generator repeats the sequence? (c) Draw the block diagram of a Differential Phase Shift Keying encoder. (iii) What design modification is necessary to increase the number of bits before the sequence repeats? (iv) What is the purpose of such a modification? [15 marks] [5 marks]