1). a). Briefly describe the following terms as applied to a signal highlighting them on a suitable sketch and discuss their significance in communications. Amplitude. Frequency. Period. Phase. b). A sine wave V(t) has an amplitude of 10 V and a frequency of 260 Hz i). Sketch a fully labelled sketch of one cycle of V(t). ii).Give the mathematical expression for V(t). iii). Calculate the value of V(t) for t = 1 s, 0.005 s and 5×10 -6 s to three decimal places. iv). Use the Agilent 33500B Function / Arbitrary Waveform Generator to verify the answers to 1). b). i), ii) and iii) include suitable plots in your assignment. v). Give a mathematical expression for the addition of two sine waves with the following parameters Wave 1. Amplitude = 5 V Frequency = 100 Hz Phase = 0 radians. Wave 1. Amplitude = 6 V Frequency = 300 Hz Phase =  radians. Briefly outline how the result could be portrayed. 3). a). Explain using a technically based description the key differences between analogue modulation and digital modulation using suitable sketches. b). A two level amplitude shift keying scheme (ASK) is implemented using square pulses of 1 microsecond duration (non return to zero) and amplitudes 1 and 5 V. The carrier frequency is a sinewave of 5MHz with amplitude 1 V. Sketch the two possible modulated waveforms (a 0 and a 1) and state the data rate assuming the pulses represent a 0 and a 1 respectively. 4). a). Explain the meaning of the term time division multiplexing and explain why it is used, give an example of a system that uses time division multiplexing. b). Four digital signals are to be time division multiplexed. A = 1 Mbit/s, B = 1 Mbit/s, C = 1 Mbit/s, D = 1 Mbit/s. i). Calculate the overall bit rate. ii.). Sketch a commutator diagram that can be used to implement this. iii). Show the connections to each channel. iv). Sketch the composite signal. v). Describe how the commutator can be used to vary the pulse width of the multiplex and accommodate different data rates. Explain why the pulse width may need to be varied and why different data rates may be needed.