Question

4) a) Draw the structure of pulse code modulation system (PCM), and explain the function of each unit in the system briefly. b) For input signal, x(t) = cos(2reft) where f = 1, design a PCM system. In your design, indicate the parameters you use clearly.

Answer 1

olution Following the Structure pem System | Analog msg. 7LPE sigral Sampler Jouanninger Encoder Regenerative Repeater Regenerative Repeater - Destination > LPF Decoder > Regeneratio Circuit LPER used as the message -> Resulting will be is Filter. anti- aliasing it rejects the high frequency components present in the inpw signal. which is greater than highest frequency of signal. band limited Sampled ace signal according to Sampsing Sampler: inis is used collect the sample data instantaneous values of message signal, im order to reconstrui the original signal, Sampling must be such that (tste 2 fm) Quantiger: round - offs each Cť the samples the the the orem, cet nearest 다 the Quantzer reduces available Quantigation voltages, the excessive bits. (h8 sampled liven Quantiger, reduces the and the value. output when the redundano گارد compress

Encoder represents Each of different quantization Voltages by unique binary code. Without quantizer Numerous of different binary generated bhich Codes needs be is not possible. L:25 noise can No. of Cuantigation cottages. - (No. of site (sample) > Channel be completely eliminated by Regenera + Repeater. - Decoder: Decoder will do ck encoder. decoder arcuit decedes pulse Coded waveforen to reproduce the original signal. So, this Circust Hue reverse ine مهم Demodulator. LPF reconstruct the message signal from ius quantized Equivalent, Bo thar finite amount of Quantigation error wi be present the reconstructed me Code signal. - Encoding is reversible but Quantigation reversible. is not Pem (Ts) Sampler Quantizer Encoder xo- Coslaaft + (OT) Sampler *EnTs) = cosants) &= 1 (Given) Ts=1 (Assumed x (nie cos@an)