6.2-6 A duobinary line coding proposed by Lender is also ternary like bipolar. In this code, a 0 is

transmitted by no pulse, and a 1 is transmitted by a pulse p(t) or -p(1) according to the following

rule. A I is encoded by the same pulse as that used for the previous 1 if there are an even

(including zero) number of Os between them. It is encoded by a pulse of opposite polarity if there

are an odd number of Os between them. Like bipolar, this code also has single-error-detection

capability, because correct reception implies that between successive pulses of the same polarity,

an even number of Os must occur, and between successive pulses of opposite polarity, an odd

number of Os must occur.

(a) Using half-width rectangular pulse, sketch the duobinary signal y() for the random binary

sequence

010110100010010...

(b) Determine Ro, R₁, and R₂ for this code.

(c) Show that R=0. n>2 for this code.

(d) Find and sketch the PSD for this line code (using half-width rectangular pulse). Show that

its effective bandwidth is Rb/2 Hz and is only half of the bipolar linecode bandwidth,

independent of the pulse shape.