Question

There is a requirement to design a digital broadcast transmission system that uses QuadratureAmplitude Modulation (QAM) and Orthogonal Frequency Division Multiplexing (OFDM). a) Explain with the aid of diagrams how

QAM encodes and decodes data and explain the difference between data rate and symbol rate.(8 marks) b) Explain with aid of diagrams why Orthogonal Frequency Division Multiplexing (OFDM)would be a suitable modulation scheme for a digital broadcast transmission system and why the symbol duration is an important design consideration?(8 marks) c) If the transmission system was capable of transmitting 64kbps with a symbol rate of 4ms.(Please show and explain all calculations for the following): Determine and justify the number of OFDM carriers. b. Explain and justify the QAM encoding level required to achieve the above.

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