$1$ Which of the signals of Table $5\mathrm{.}2$ use differential encoding?

$5\mathrm{.}2$ Develop algorithms for generating each of the codes of Table $5\mathrm{.}2$ from NRZ$-$L$.$

$5\mathrm{.}3$ A modified NRZ code known as enhanced$-$NRZ $($E$-$NRZ$)$ is sometimes used for

high$-$density magnetic tape recording. E$-$NRZ encoding entails separating the

NRZ$-$L data stream into $7-$bit words; inverting bits $2,3,6,$ and $7$; and adding one

parity bit to each word. The parity bit is chosen to make the total number of $1$s in

the $8-$bit word an odd count. What are the advantages of E$-$NRZ over NRZ$-$L$?$ Any

disadvantages?