One time period of a periodic signal ft) is shown in Figure Q1 below. 4 t/ms Figure Q1 (a) Derive the complex Fourier Series of f(t). (b) From the complex Fourier Series of fl(t) obtained from (a), deduce the trigonometrical Fourier Series of At) and hence sketch its magnitude spectrum up to the 5th harmonic. (c) fit) is passed through a lowpass filter with cutoff frequency of 200 Hz. Sketch a graph of the received signal in time domain, clearly labelling the axes.