Exercise $2$: Assume that $Vr=6V,$ find the value of $R$ to obtain the transfer characteristic shown in the Figure.

Exercise $3$: Design a R$-$wave detector for an ECG signal that has

R$-$wave magnitude that varies between $1\mathrm{.}0$ V and $1\mathrm{.}4$ V

$50$ Hz interference $100$ mV peak$-$to$-$peak

T$-$wave magnitude that varies between $0\mathrm{.}5$ V and $0\mathrm{.}7$ V

Use reasonable values for electronic components, power supplies and saturation voltages.

Hints: Comparator with hysteresis, use standard values for resistors.