Digital Logic & Number representation

Question 241

The Hexadecimal equivalent of 01111100110111100011 is

• CD73E
• ABD3F
• 7CDE3
• FA4CD

Question 242

The BCD adder to add two decimal digits needs minimum of

• 6 full adders and 2 half adders
• 5 full adders and 3 half adders
• 4 full adders and 3 half adders
• 5 full adders and 2 half adders

Question 243

The Excess-3 decimal code is a self-complementing code because (1)The binary sum of a code and its 9’s complement is equal to 9. (2)It is a weighted code. (3)Complement can be generated by inverting each bit pattern. (4)The binary sum of a code and its 10’s complement is equal to 9.

• (1)
• (2) and (3)
• (1) and (3)
• All are correct.

Question 244

The range of representable normalized numbers in the floating point binary fractional representation in a 32-bit word with 1-bit sign, 8-bit excess 128 biased exponent and 23-bit mantissa is

• 2^-128 to (1 – 2^-23 ) × 2¹²⁷
• (1 – 2 ^–23 ) × 2 ^–127 to 2¹²⁸
• (1 – 2 ^–23 ) × 2 ^–127 to 2 ²³
• 2 ^–129 to (1 – 2 ^–23 ) × 2 ¹²⁷

Question 245

The period of a signal is 10 ms. What is its frequency in Hertz?

• 10
• 100
• 1000
• 10000

Question 246

‘FAN IN’ of a component A is defined as

• Count of the number of components that can call, or pass control, to a component A
• Number of components related to component A
• Number of components dependent on component A
• None of the above

Question 247

In the diagram above, the inverter (NOT gate) and the AND-gates labeled 1 and 2 have delays of 9, 10 and 12 nanoseconds(ns), respectively. Wire delays are negligible. For certain values of a and c, together with certain transition of b, a glitch (spurious output) is generated for a short time, after which the output assumes its correct value. The duration of the glitch is

• 7 ns
• 9 ns
• 11 ns
• 13 ns

Question 248

Any set of Boolean operators that is sufficient to represent all Boolean expressions is said to be complete. Which of the following is not complete?

• { AND, OR }

• { AND, NOT }

• { NOT, OR }

• { NOR }

Question 249

If a variable can take only integral values from 0 to n, where n is an integer, then the variable can be represented as a bit-field whose width is (the log in the answers are to the base 2, and [log n] means the floor of log n)

• [log(n)] + 1 bits
• [log (n-1)) + 1 bits
• [log (n+1)] + 1 bits
• None of the above

Question 250

Given √224_r = 13_r the value of radix r is

• 10
• 8
• 6
• 5