$($b$)$ How is the R$-2$R ladder network different from the weighted resistance type network used to design a digital to analog converter? Draw the complete $4-$bit R$-2$R ladder network and use it to convert a digital input $0110$ into an analog equivalent output. Assume $\text{'}0\text{'}=0V$ and $\text{'}1\text{'}=15V$ as input.

$8$