The two middle terms are zero: fort>lo,n(t) and are uncorrelated becauset) is white(impulse correlation function) For=, n() has a finite effect on x()because n() is white. But the integral of a finite quantity over one point is zero
Codes in binary system BCD codes: for decimal digit Gray code: for numbers in binary system; AsCIi code: for characters ey point Use n bits. we can make 2n different words: To make n code-words. you must use logn bits