Online Test 4 - Digital Logic and Circuit Design

GATE Online practice test Digital Logic and Circuit Design

15 Questions Published

Questions

Question 1 Multiple Choice (Single Answer)

Let A = 1111110 and B = 0000 1010 be two 8 - bit 2's complement numbers. Their product in 2's complement is

  1. 1100 0100
  2. 1001 1100
  3. 1010 0101
  4. 1101 0101
Question 2 Multiple Choice (Single Answer)

Consider the partial implementation of a 2 - bit counter using T flip flops following the sequence 0 - 2- 3 - 1 - 0, as shown below:

To complete the circuit, input X should be

  1. Q2`
  2. Q2 + Q1
  3. (Q1 $\oplus$Q2)`
  4. Q1 $\oplus$Q2
Question 3 Multiple Choice (Single Answer)

How many addresses are required for 50 × 20 video RAM?

  1. 1020
  2. 1920
  3. 100
  4. 1000
Question 4 Multiple Choice (Single Answer)

Let the clock cycles required for various operations be as follows:
Register to/from memory transfer: 3 clock cycles
Add with both operand in register: 1 clock cycle
Instruction fetch and decode: 2 clock cycles per word

The total number of clock cycles required to execute the program, is

  1. 29
  2. 24
  3. 23
  4. 20
Question 5 Multiple Choice (Single Answer)

The switching expression corresponding to
f(A, B, C, D)= $\sum(1,4,5,9,11,12)$ is

  1. BC' D' + A'C'D + AB'D
  2. ABC' + ACD + B'C'D
  3. ACD' + A' BC' + AC'D'
  4. A'BD + ACD' + BCD'
Question 6 Multiple Choice (Single Answer)

Which of the following is the 2's complement of the number 10101?

  1. 01010
  2. 10101
  3. 01011
  4. None of these
Question 7 Multiple Choice (Single Answer)

Which of the following can be used to conveniently test odd parity of the word?

  1. XOR gate
  2. NOR gate
  3. OR gate
  4. None of these
Question 8 Multiple Choice (Single Answer)

By which of the following electronic components, is EPROM made up?

  1. Diodes
  2. MOSFETs
  3. Bipolar transistors
  4. None of these
Question 9 Multiple Choice (Single Answer)

Which of the following is true about a simple flip flop?

  1. It is a 1-bit memory latch.
  2. It is a 2-bit memory latch.
  3. It is not a memory element.
  4. None of these
Question 10 Multiple Choice (Single Answer)

Which of the following is true about the semiconductor memory?

  1. Somewhat slower than magnetic core memory
  2. Somewhat larger than the magnetic core memory
  3. Both 1 and 2
  4. A volatile memory
Question 11 Multiple Choice (Single Answer)

Which of the following is the basic purpose of using FETs in case of linear ICs?

  1. These provide large resistances.
  2. These increase input resistance.
  3. These decrease input resistance.
  4. Both (1) and (2)
Question 12 Multiple Choice (Single Answer)

Consider the following circuit.

Flip Flop

The flip-flops are positive edge triggered D FFs. Each state is designated as a two bit string Q0Q1. Let the initial state be 00. The state transition sequence is:

  1. ![Option][1]


    [1]: http://i.imgur.com/f917EZ6.png
  2. ![be][1]


    [1]: http://i.imgur.com/ZQzJDKd.png
  3. ![c][1]


    [1]: http://i.imgur.com/tXTzbME.png
  4. ![d][1]


    [1]: http://i.imgur.com/6xVwrXk.png
Question 13 Multiple Choice (Single Answer)

A dynamic RAM call, which holds 5V, has to be refreshed every 20 m/sec such that stored voltage does not fall below 0.5V. If the call has a constant discharge current of 0.1 pA, the storage capacitance of the call is

  1. 4 × 10-6
  2. 4 × 10-9
  3. 4 × 10-12
  4. 4 × 10-15
Question 14 Multiple Choice (Single Answer)

Consider the following set of instruction:
MVI A, BYTE1
RLC
MOV B, A
RLC
RLC
ADD B
If BYTE1 = 07H, then content of A, after the execution of program, will be

  1. 46H
  2. 70H
  3. 38H
  4. 68H
Question 15 Multiple Choice (Single Answer)

The range of integers that can be represented by an n bit 2's complement number system, is

  1. -2n - 1 to (2n -1 - 1)
  2. -(2n -1)to (2n -1 - 1)
  3. -2n - 1 to 2n -1
  4. -(2n +1)to (2n -1 - 1)