(a) Given a sinusoidal signal x(t) as shown in Fig. 4 is to be transmitted over a PCM system. i. ii. iii. iv. 8 i. ii. 6 iii. iv. Ampplitude (V) IN 5e-05 0.0001 0.00015 0.0002 0.00025 0.0003 Time (Second) Fig. 4 If the sampling frequency is 25 kHz and the number of bits of each sample is 10 bits. Find the following: 4 -2 -4 0 Full range Vf of the x(t), quantization step 4V and quantization noise in V (5 marks) Signal to noise ratio in dB (2 marks) (b) In a digital transmission, a bit stream m[n] = 110101 is modulated by phase shift keying (PSK) signal expressed as xc(t) = Nyquist rate of x(t) in Hz (3 marks) Is it possible to recover the signal if the sampling frequency is reduced to 18kHz? Please explain. (3 marks) (2cos(2t) -2cos(2nt) for a "1" bit for a "0" bit Sketch the modulated signal in time domain How can the PSK signal be demodulated? Name one method to reduce the intersymbol interference Name one method to improve spectral efficiency (6 marks) (2 marks) (2 marks) (2 marks)