Digital Principles and System Design January 28, 2019 Vijayan 0 Systems design implies a systematic approach to the design of a system. It may take a bottom-up or top-down approach, but either way the process is systematic wherein it takes into account all related variables of the system that needs to be created—from the architecture, to the required hardware and software, right down to the data and how it travels and transforms throughout its travel through the system. Systems design then overlaps with systems analysis, systems engineering and systems architecture. An important drawback of binary system is It requires very large string of 1’s and 0’s to represent a decimal number It requires sparingly small string of 1’s and 0’s to represent a decimal number It requires large string of 1’s and small string of 0’s to represent a decimal number None of the Mentioned What is the addition of the binary numbers 11011011010 and 010100101? 0111001000 1100110110 11101111111 10011010011 Perform binary addition: 101101 + 011011 = ? 011010 1010100 101110 1001000 Perform binary subtraction: 101111 – 010101 = ? 100100 010101 011010 011001 Perform multiplication of the binary numbers: 01001 × 01011 = ? 001100011 110011100 010100110 101010111 Divide the binary numbers: 111101 ÷ 1001 and find the remainder 0010 1010 1100 0011 Divide the binary number (011010000) by (0101) and find the quotient 100011 101001 110010 010001 Logic circuitry is used to detect Underflow MSD Overflow LSD 1’s complement can be easily obtained by using Comparator Inverter Adder Subtractor The advantage of 2’s complement system is that Only one arithmetic operation is required Two arithmetic operations are required No arithmetic operations are required None of the Mentioned Which one is used for logical manipulations ? 2’s complement 9’s complement 1’s complement 10’s complement Binary coded decimal is a combination of Two binary digits Three binary digits Four binary digits None of the Mentioned The decimal number 10 is represented in its BCD form as 1010 01010 00010000 001010 Carry out BCD subtraction for (68) – (61) using 10’s complement method. 00000111 01110000 100000111 011111000 Code is a symbolic representation of __________ information. Continuous Discrete binary None of the Mentioned When numbers, letters or words are represented by a special group of symbols, this process is called Decoding Encoding Coding None of the Mentioned How many bits would be required to encode decimal numbers 0 to 9999 in straight binary codes. 12 14 16 18 DeMorgan’s theorem states that (AB)’ = A’ + B’ (A + B)’ = A’ * B A’ + B’ = A’B’ None of the Mentioned In boolean algebra, the OR operation is performed by which properties? Associative properties Commutative properties Distributive properties All of the Mentioned The boolean function A + BC is a reduced form of AB + BC (A + B)(A + C) A’B + AB’C (A + C)B The logical sum of two or more logical product terms is called SOP POS OR operation NAND operation A product term containing all K variables of the function in either complemented or uncomplemented form is called a Minterm Maxterm Midterm None of the Mentioned According to the property of minterm, how many combination will have value equal to 1 for K input variables? 0 1 2 3 A Karnaugh map (K-map) is an abstract form of ____________ diagram organized as a matrix of squares. Venn Diagram Cycle Diagram Block diagram Triangular Diagram The prime implicant which has at least one element that is not present in any other implicant is known as Essential Prime Implicant Implicant Complement None of the Mentioned These logic gates are widely used in _______________ design and therefore are available in IC form. Circuit Digital Analog Block In which of the following gates the output is 1 if and only if at least one input is 1? AND NOR NAND OR What is the minimum number of two input NAND gates used to perform the function of two input OR gates? One Two Three Four The number of full and half adders are required to add 16-bit number is 8 half adders, 8 full adders 1 half adders, 15 full adders 16 half adders, 0 full adders 4 half adders, 12 full adders Which of the following will give the sum of full adders as output? Three point major circuit Three bit parity checker Three bit comparator Three bit counter How is an encoder different from a decoder? The output of an encoder is a binary code for 1-of-N input The output of a decoder is a binary code for 1-of-N input The output of an encoder is a binary code for N-of-1 output The output of an decoder is a binary code for N-of-1 output How many OR gates are required for a Decimal-to-bcd encoder? 2 10 3 4 Can an encoder be called as multiplexer? No Yes Sometimes Never Which of the following is correct for a gated D-type flip-flop? The Q output is either SET or RESET as soon as the D input goes HIGH or LOW The output complement follows the input when enabled Only one of the inputs can be HIGH at a time The output toggles if one of the inputs is held HIGH The only difference between a combinational circuit and a flip-flop is that The flip-flop requires previous state The flip-flop requires next state The flip-flop requires a clock pulse None of the Mentioned The flip-flop is only activated by Positive edge trigger Negative edge trigger Either positive or Negative edge trigger None of the Mentioned Which statement BEST describes the operation of a negative-edge-triggered D flip-flop? The logic level at the D input is transferred to Q on NGT of CLK The Q output is ALWAYS identical to the CLK input if the D input is HIGH The Q output is ALWAYS identical to the D input when CLK = PGT The Q output is ALWAYS identical to the D input The characteristic equation of D-flip-flop implies that The next state is dependent on previous state The next state is dependent on present state The next state is independent of previous state The next state is independent of present state In digital logic, a counter is a device which Counts the number of outputs Stores the number of times a particular event or process has occurred Stores the number of times a clock pulse rises and falls None of the Mentioned Synchronous counter is a type of SSI counters LSI counters MSI counters VLSI counters BCD counter is also known as Parallel counter Decade counter Synchronous counter VLSI counter The parallel outputs of a counter circuit represent the Parallel data word Clock frequency Counter modulus Clock count One of the major drawbacks to the use of asynchronous counters is that: Low-frequency applications are limited because of internal propagation delays High-frequency applications are limited because of internal propagation delays Asynchronous counters do not have major drawbacks and are suitable for use in high- and low-frequency counting applications Asynchronous counters do not have propagation delays, which limits their use in high-frequency applications How many flip-flops are required to construct a decade counter? 4 8 5 10 How many different states does a 3-bit asynchronous counter have? 2 4 8 16 How many different states does a 2-bit asynchronous counter have? 1 4 2 8 The set inputs are used in a decade counter, why? To set the counter to 0011 To set the counter to 1000 To set the counter to 1001 To set the counter to 0001 Integrated-circuit counter chips are used in numerous applications including: Timing operations, counting operations, sequencing, and frequency multiplication Timing operations, counting operations, sequencing, and frequency division Timing operations, decoding operations, sequencing, and frequency multiplication Data generation, counting operations, sequencing, and frequency multiplication Which of the following statements are true? Asynchronous events does not occur at the same time Asynchronous events are controlled by a clock Synchronous events does not need a clock to control them Only asynchronous events need a control clock A down counter using n-flip-flops count Downward from a maximum count Upward from a minimum count Downward from a minimum to maximum count None of the Mentioned UP Counter is It counts in upward manner It count in down ward manner It counts in both the direction None of the mentioned How many different states does a 3-bit asynchronous down counter have? 2 4 6 8 In a 3-bit asynchronous down counter, at the first negative transition of the clock, the counter content becomes 000 111 101 010 The hexadecimal equivalent of 15,536 is ________ 3CB0 3C66 63C0 6300 A register is defined as The group of latches for storing one bit of information The group of latches for storing n-bit of information The group of flip-flops suitable for storing one bit of information The group of flip-flops suitable for storing binary information How many methods of shifting of data are available? 2 3 4 5 Ring shift and Johnson counters are: Synchronous counters Asynchronous counters True binary counters Synchronous and true binary counters What is the difference between a shift-right register and a shift-left register? There is no difference The direction of the shift Propagation delay The clock input What is a transceiver circuit? A buffer that transfers data from input to output A buffer that transfers data from output to input A buffer that can operate in both directions None of the Mentioned What is the function of a buffer circuit? To provide an output that is inverted from that on the input To provide an output that is equal to its input To clean up the input To clean up the output

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