2016 Question 4 (20 marks) (a) What does AM stands for? and (b) What does FM stands for. Suppose that a signal to be transmitted can be expressed as: v(t) = 10 sin (100 t t +) (c) Use a carrier frequency of 500 Hz to sketch the AM signal modulated by v(t); and (d) If a carrier frequency of 1 kHz is used for FM modulation, sketch the modulated signal with v(t). Note: In both (c) and (d) cases, explain your sketches to gain full marks