I did this topic when I was at school, so I'll give you some advice. I will use the follower operational amplifier in the input peripheral circuit (not to mention how to use it, just connect it directly) (plus filter circuit), and then use the voltage comparator to introduce the reference voltage for comparison. After comparison, the signal is input into the internal program of FPGA chip. Huang's book is very detailed, with an external led display. Pay attention to the voltage range of each part and add some resistors appropriately. Everything in the book can be completed very smoothly. Therefore, I suggest that your paper should be carefully written with peripheral circuit programs, and it is nothing to simulate according to the steps in the book. Of course, the paper can refer to some other (such as background technology) and I hope you can pass the design smoothly. I think this is relatively simple. Come to think of it, there is absolutely no problem. It is strongly recommended that you buy a piece of paper or a circuit diagram.