In BCD addition, what correction factor must be added when an illegal code (> 1001) or carry out occurs?
When a 4-bit sum exceeds 9 or produces a carry, adding 0110 (decimal 6) skips the 6 invalid 4-bit combinations and corrects the BCD result.
What is the primary advantage of 2's complement over 1's complement representation?
1's complement has two representations for zero (+0 as 0000 and -0 as 1111), whereas 2's complement has a single unique representation for zero (00000000).
In Hamming single-error-correcting code for a 4-bit data word, how many parity check bits are required?
The Hamming relation is $2^p$ >= d + p + 1. For data length d = 4: if p = 3, $2^3$ = 8 >= 4 + 3 + 1 = 8. Hence, 3 parity bits are required.
Convert the decimal fraction 0.625 to binary.
$625 * 2 = 1.25 (1), 0.25 * 2 = 0.5 (0), 0.5 * 2 = 1.0 (1). Combining fractional bits yields 0.101_2.$
Which character encoding system uses a 7-bit standard code to represent 128 characters?
Standard ASCII uses 7 bits per character, accommodating $2^7$ = 128 distinct control and printable characters.