hi all
this is something related to basics of digital ckt.
how many NAND gates are required to implement a function like ABC or is there any formula to calculate the number of gates to implement a n-variable function
There is no "Formula " to calculate the number of nand gates required for any n-variable function . U simply have to deduce it using your knowledge of digital electronics . Going a bit further the number of gates required is not directly related to number of variables but the complexity in the function to be implemented . For ex. a function like ABCD will require a lot less gates than (AB)'.C.(A+B) , even though the second function has only 3 variables it is going to take a lot more gates to implement this . Hope I have cleared your doubt .
That sounds more like a look-up table. Anyway, Karnaugh maps do not give you look-up tables. It's just a systematic way of identifying redundancies to reduce gate count.
This question is on digital circuits, but is nowhere near basics. EDA logic synthesis tools are used to answer such questions, and they can employ entire computer clusters just to compute these values.