Meaning of A/D conversion noise

Question

What is the meaning of A/D conversion noise?

Answer 1

A DSP consists of the device, A/D converter which operates upon the analog input x (t) to generate the xq(t) that is binary sequence of 0s and 1s.  At first signal x (t) is sampled at the regular intervals in order to generate the sequence x (n) is of infinite precision. Every sample x (n) is expressed in terms of the finite number of bits provided in the sequence xq(n). The difference of signal e (n) =xq(n)-x(n) is known as A/D conversion noise.