(a) In the so-called folded binary code of 4 bits, the left most digit represents the sign of an analog signal's quantized samples (with 0 for negative and 1 for positive), and the next three digits are the natural binary codewords for the magnitude of the quantized samples.

Obtain a table of binary code words.

(b) By letting the digit sequence in part (a) be b4b3b2b1, which also represents a 4-bit natural binary code for 16 levels labeled 0 through 15, obtain the digit sequence g₄g₃g₂g₁, where

which is known as the Gray code. A unique characteristic of the Gray code is that code words change in only one digit between ad- jacent levels. Check the same in your result.