In the name of ALLAH, the most beneficient, the most merciful

Digital Logic Design (CS302)

Multiple Choice Questions (MCQs)

Objective Questions

  1. In NAND based S-R latch, output of each ________ gate is connected to the input of the other ________ gate.

    1. NOR, NAND
    2. NAND, NOR
    3. NOR, NOR
    4. NAND, NAND
  2. Two signals ________ and ________ provide the timing inputs to the State Machine.

    1. NSSR and EWSR
    2. LTIME and STIME
    3. PTIME and QTIME
    4. NSGrn and NSYel
  3. In the keyboard encoder, how many times per second does the ring counter scan the key board?

    1. 600 scans/second
    2. 625 scans/second
    3. 650 scans/second
    4. 700 scans/second
  4. A 3-variable karnaugh map has

    1. eight cells
    2. three cells
    3. sixteen cells
    4. four cells
  5. The n flip-flops store ________ states.

    1. 1
    2. 2^n
    3. 0
    4. 2^(n+1)
  6. Subtractors also have output to check if 1 has been ________.

    1. Primed
    2. Shifted
    3. Complemented
    4. Borrowed
  7. Flash memory Operation are classified into ________ different operation.

    1. Two
    2. Three
    3. Four
    4. Five
  8. In distributed mode, for a 1024 x 1024 DRAM memory and a refresh cycle of 8 msec, each of the 1024 rows has to be refreshed in ________ when Distributed refresh is used.

    1. 4.8 microsec
    2. 5.9 microsec
    3. 7.8 microsec
    4. 5.5 microsec
  9. For a down counter that counts from (111 to 000), if current state is "101" the next state will be ________.

    1. 111
    2. 110
    3. 010
    4. None of the given
  10. The Static Ram (SRAM) is non-volatile and is not a ________ density memory as a latch is required to store a single bit of information.

    1. Low
    2. High
    3. Medium
    4. Hot
  11. A 4-bit binary up/down counter is in the binary state of zero. The next state in the DOWN mode is:

    1. 0001
    2. 1000
    3. 1110
    4. 1111
  12. The 64-cell array organized as 8 x 8 cell array is considered

    1. as an 64 byte memory
    2. as a 16 byte memory
    3. as an 8 byte memory
    4. as an 4 byte memory
  13. Which of the following Output Equations determines the output of the State Machine?

    1. MIN = Q0Q1
    2. MAX = Q0Q1EN
    3. MIN = Q0Q1EN
    4. MAX = Q1EN
  14. Consider A=1, B=0, C=1. A, B and C represent the input of three bit NAND gate, the output of the NAND gate will be ________.

    1. Zero
    2. One
    3. Undefined
    4. No output as input is invalid
  15. GAL can be reprogrammed as instead of fuses E2CMOS logic is used which can be programmed to connect a ________ with a ________.

    1. column, row
    2. row, column
    3. column, column
    4. row, row
  16. The CONSTATE.CLK = Clock is used to indicate that the ________ state variables change on a clock transition.

    1. CONSTATE
    2. FLOOR
    3. MOTION
    4. OPEN
  17. Implementing the Adjacent 1s detector circuit directly from the function table based on the SOP form requires ________ gates for the 8 product terms (minterms) with an 8-input OR gate.

    1. 8 OR
    2. 8 AND
    3. 8 XOR
    4. 8 NOR
  18. The outputs of SR latches in elevator state machine are feed back to the ________ gate array for connection to the D-flipflops.

    1. NOT
    2. AND
    3. OR
    4. XOR
  19. Adding two octal numbers "36" and "71" result in ________.

    1. 213
    2. 123
    3. 127
    4. 345
  20. PLDs have In-System Programming (ISP) capability that allows the ________ to be programmed after they have been installed on a circuit board.

    1. PLAs
    2. PALs
    3. PLDs
    4. EPROM
  21. Which of the following is a volatile memory?

    1. PROM
    2. DRAM
    3. EPROM
    4. EEPROM
  22. The next state table for REQ1, FLOOR1 and OPEN inputs indicates that the ________ can be pressed at any time either on the first floor or the second floor in elevator.

    1. REQ0
    2. OPEN
    3. REQ1
    4. FLOOR1
  23. Two types of memories namely the first in-first out (FIFO) memory and last in first out (LIFO) are implemented using ________.

    1. Shift Registers
    2. Circular Buffers
    3. Ring Buffers
    4. Reduce Registers
  24. Divide-by-32 counter can be achieved by using

    1. Flip-Flop and DIV 10
    2. Flip-Flop and DIV 16
    3. Flip-Flop and DIV 32
    4. DIV 16 and DIV 32
  25. In memory write cycle, the time for which the WE signal remains active is known as the ________.

    1. Write address setup
    2. Write pulse width
    3. Write delay width
    4. Write data time
  26. In DRAM read cycle R /W- signal is activated to read data which is made available on the ________ data line.

    1. D(IN)
    2. D(OUT)
    3. D(AB)
    4. D(INT)
  27. The Synchronous SRAM also has a Burst feature which allows the Synchronous SRAM to read or write up to ________ location(s) using a single address.

    1. One
    2. Two
    3. Three
    4. Four
  28. The terminal count of a 4-bit binary counter in the UP mode is ________.

    1. 1100
    2. 0011
    3. 1111
    4. 0000
  29. The Adjacent 1s Detector accepts 4-bit inputs. If ________ adjacents 1s are detected in the input, the output is set to high.

    1. 2
    2. 4
    3. 1
    4. 0
  30. The ABEL Input file can use a ________ instead of the equation to specify the Boolean expressions.

    1. Truth Table
    2. State Diagram
    3. Karnaugh Map
    4. Logic Circuit
  31. The maximum value, represented by a single hexadecimal digit is ________.

    1. "E"
    2. "F"
    3. "G"
    4. "H"
  32. A decade counter can be implemented by truncating the counting sequence of a MOD-20 counter.

    1. True
    2. False
  33. PALs tend to execute ________ logic.

    1. SPD
    2. SOP
    3. SAC
    4. SAP
  34. ________ Counters as the name indicates are not triggered simultaneously.

    1. Asynchronous
    2. Synchronous
    3. Positive-Edge triggered
    4. Negative-Edge triggered
  35. Implementation of the FIFO buffer in ________ is usually takes the form of a circular buffer.

    1. RAM
    2. ROM
    3. PPROM
    4. Flash Memory
  36. If the voltage drop across the active load is 0 volts due to absence of current the comparator output is a ________.

    1. 0
    2. 1
  37. Consider the sum of weight method for converting decimal into binary value, ________ is the highest weight for 411.

    1. 64
    2. 128
    3. 256
    4. 512
  38. The 74HC163 is a 4-bit Synchronous counter, it has ________ data output pins.

    1. 2
    2. 4
    3. 6
    4. 8
  39. Implementation of Latch is required almost ________ transistor.

    1. Two
    2. Four
    3. Six
    4. Eight
  40. The normal data inputs to a flip-flop (D, S and R, J and K, T) are referred to as ________ inputs.

    1. Sequential
    2. Asynchronous
    3. Synchronous
    4. Combinational
  41. Demorgan's two theorems prove the equivalency of the NAND and ________ gates and the NOR and ________ gates respectively.

    1. Negative-OR, Negative-AND
    2. Negative-AND, Positive-OR
    3. Positive-OR, Negative-AND
    4. Positive-OR, Positive-AND
  42. In case of cascading Integrated Circuit counters, the enable inputs and RCO of the Integrated Circuit counters allow cascading of multiple counters together.

    1. True
    2. False
  43. For a Standard SOP expression, a ________ is placed in the cell corresponding to the product term (Minterm) present in the expression.

    1. 0
    2. 1
    3. x (don't care condition)
    4. Any of given option depending on SOP term
  44. The AND Gate performs a logical ________ function.

    1. Addition
    2. Substraction
    3. Multiplication
    4. Division
  45. The Test Vector definition defines the test vectors for all the three counter inputs and ________ counter output/outputs.

    1. One
    2. Two
    3. Three
    4. Four
  46. The ROM used by a computer is relatively ________ as it stores few byres of code used to Boot the Computer system on power up.

    1. Small
    2. Large
    3. Heavy
    4. High
  47. The domain of the expression AB'CD + AB' + C'D + B is

    1. A and D
    2. B only
    3. A, B, C and D
    4. None of the given
  48. The ________ input overrides the ________ input.

    1. Asynchronous, synchronous
    2. Synchronous, asynchronous
    3. Preset input (PRE), Clear input (CLR)
    4. Clear input (CLR), Preset input (PRE)
  49. ________ is used when the output is connected back to the input of the PAL or if the output pin is used as an input only.

    1. Combinational Input/Output
    2. Combinational Output
    3. Combinational Input
    4. Programmable polarity
  50. If two numbers in BCD representation generate an invalid BCD number then the binary ________ is added to the result.

    1. 1001
    2. 0110
    3. 1111
    4. 1100
  51. Select the mode of programming in which GAL16V8 can be programmed:

    1. Simple Mode
    2. Complex Mode
    3. Registered Mode
    4. All of the given
  52. A multiplexer with a register circuit converts

    1. Serial data to parallel
    2. Parallel data to serial
    3. Serial data to serial
    4. Parallel data to parallel
  53. You have to choose suitable option when your timer will reset by considering this given code:
    TRSTATE.CLK = clk;
    TMRST: = (TRSTATE = = NSY2) # (TRSTATE = = EWY2);

    1. NSY2 or EWY2
    2. NSSR or TMRST
    3. EWSR or NSRED
    4. EWRed or EWYel
  54. The output of a NAND gate is ________ when all the inputs are one.

    1. Zero
    2. One
    3. Available
    4. Not available
  55. As data values are written or read from the RAM Stack Pointer Register increments or decrements its contents always pointing to the stack ________.

    1. Bottom
    2. Top
    3. Down
    4. Vertex
  56. Canonical form is a unique way of representing ________.

    1. SOP
    2. Minterm
    3. Boolean Expression
    4. POS
  57. The FAST Model Page Access allows ________ memory read and access times when reading successive data values stored in consecutive locations on the same row.

    1. Slow
    2. Faster
    3. Medium
    4. Modern
  58. An Asynchronous Down-counter is implemented (Using J-K flip-flop) by connecting ________.

    1. Q output of all flip-flops to clock input of next flip-flops
    2. Q' output of all flip-flops to clock input of next flip-flops
    3. Q output of all flip-flops to J input of next flip-flops
    4. Q' output of all flip-flops to K input of next flip-flops
  59. The S-R latch has two inputs, therefore ________ different combinations of inputs can be applied to control the operation of the S-R latch.

    1. two
    2. four
    3. eight
    4. sixteen
  60. The ________ gate and ________ gate implementation connected at the B input of the 4-bit Adder is used to allow Complemented or Un-Complemented B input to be connected to the Adder input.

    1. AND, NOR
    2. AND, NOT
    3. AND, OR
    4. XOR, NAND
  61. The NOR logic gate is the same as the operation of the ________ gate with an inverter connected to the output.

    1. AND
    2. NAND
    3. OR
    4. NOT
  62. Memory is arranged in ________.

    1. linear fashion
    2. two-dimensional manner
    3. three-dimensional manner
    4. random fashion
  63. Why demultiplexer is called a data distributor?

    1. The input will be distributed to one of the outputs
    2. The input will be selected for the output
    3. The output will be distributed to one of the inputs
    4. Single input to Single Output
  64. Cin is part of ________ Adder.

    1. Half
    2. Full
    3. Single
    4. Double
  65. A NOR based S-R latch is implemented using ________ gates instead of ________ gates.

    1. XOR, NAND
    2. NOR, XOR
    3. NOR, NAND
    4. OR, XOR
  66. A SOP expression can be implemented by an ________ combination of gates.

    1. OR-XOR
    2. AND-NAND
    3. AND-OR
    4. XOR-NOR
  67. 8-bit parallel data can be converted into serial data by using ________ multiplexer.

    1. 4-to-2
    2. 8-to-1
    3. 4-to-4
    4. 8-to-4
  68. Which signal must remain valid in memory write cycle after data is applied at the data input lines and must remain valid for a minimum time duration tWD?

    1. -CS
    2. -WE
    3. W
    4. OE
  69. UVERPROM is stands for

    1. Ultra-Variant
    2. Ultra-Vibrant
    3. Ultra-Voilet
    4. Ultra-Visible
  70. If the number of samples that are collected is reduced by half, the reconstructed signal will be ________ from/to the original.

    1. Different
    2. Same
    3. Equal
    4. Opposite
  71. The Transition table is very similar to the ________ table.

    1. Truth
    2. State
    3. Transition
    4. None of the given
  72. Which one flip-flop has an invalid output state?

    1. T
    2. JK
    3. SR
    4. D
  73. When the transmission line is idle in an asynchronous transmission

    1. It is set to logic low
    2. It is set to logic high
    3. It remains in previous state
    4. State of transmission line is not used to start transmission