please forgiven my poor english, i will try my best to express.
in question a i find out Vul have to be 3V and Vll = 1V ,but i googled window comparator,
although i know Vmax and Vmin is depend on R1 and R2 , i still dont know how to choose a correct values for these.
also above the R1, what is the +5V??
and what are those diodes for?? i only know when Vin= 4V , D2 break down, D1 forward , produces logic high for voltages...
sorry about my english, please help me...