[sukatoa]

Quote:

int excellent;
int low;
int poor;
int verygood;
int good;
int nosignal;

you may initialize first some values above.

Quote:

System.out.println("Please enter x1");
System.out.println("Please enter x2");

You may read Scanner class for capturing inputs from keyboard... nextInt() method may fit your needs

Quote:

System.out.println("your type of signal is:");

How about concat(String s) method?

eg. System.out.println("Signal type is".concat(y));

or System.out.println("Signal type is"+y);
or System.out.printf("Signal type is %s\n",y); C type