The following 8-bit data sample sequence is to be encoded for transmission: a. How many bits will be required to transmit this sequence if Pulse Code Modulation (PCM) is used? (1 mark) b. If Differential Pulse Code Modulation (DPCM) encoding is now used, what will be the full DPCM sequence? (2 marks) c. Hence, calculate the number of bits required to transmit this DPCM sequence. (1 mark) d. What approximate compression ratio is achieved by DPCM compared with PCM for this sequence? (1 mark)