Explore topic-wise InterviewSolutions in .

Correct option is (B) 4-bit MAGNITUDE COMPARATOR

The best I can explain: TTL 74LS85 is a 4-bit magnitude comparator.

The correct option is (d) To compare a set of variables or unknown NUMBERS

The explanation: A comparator is a combinational circuit that takes two numbers as input in binary form and results WHETHER one input is greater, lesser or equal to the other input. The PURPOSE of a Digital Comparator is to compare a set of variables or unknown numbers, for example A (A1, A2, A3, …. An, etc) against that of a constant or unknown value such as B (B1, B2, B3, …. Bn, etc) and produce an output condition or flag depending upon the result of the comparison.

The correct OPTION is (C) Three output terminals

Explanation: A Magnitude Comparator is a DIGITAL comparator which has three output terminals, ONE each for equality, A = Bgreater than, A > Band less than A < B.

Right choice is (a) Only one output terminal

The best I can explain: An IDENTITY Comparator is a digital comparator that has only one output terminal for when A = B EITHER “HIGH”A = B = 1 or “LOW”A = B = 0.

The correct OPTION is (B) 2

For explanation: There are two main types of Digital COMPARATOR available and these are: Identity Comparator & Magnitude Comparator. Identity Comparator checks only the EQUALITY of the inputs and thus has one output terminal. While Magnitude Comparator checks for greater than, less than as well as equality of the inputs, and thus has 3 output terminals.

The correct OPTION is (a) Algorithm

Easy explanation: A procedure that SPECIFIES FINITE set of STEPS is called algorithm, While a flowchart is a pictorial representation of the algorithm.

The correct OPTION is (d) Magnitude comparator

For explanation I would SAY: A comparator is a combinational circuit that takes two numbers as input in binary form and results whether one input is GREATER, LESSER or equal to the other input.A circuit that COMPARES two numbers and determine their magnitude is called magnitude comparator.

Right ANSWER is (b) CPU

The explanation: Comparators are used in the CENTRAL processing unit (CPUs). Because all the arithmetic and LOGICAL operations are PERFORMED in the ALU(Arithmetic Logic Unit) part of the CPU.

The correct answer is (a) 1

The explanation is: A comparator is a COMBINATIONAL CIRCUIT that takes two numbers as input in binary form and results whether ONE input is greater, lesser or equal to the other input. If A > B, it means that it SATISFIES one of the condition among three. Hence the output will be 1.

The correct CHOICE is (a) XOR

The explanation is: GENERALLY, an XNOR outputs high for even number of 1s or all 0s and outputs LOW for otherwise. Thus, an XNOR gate is a basic comparator, because its output is “1” only if its two input bits are equal.

The correct answer is (a) 0

To explain: A comparator is a COMBINATIONAL circuit that TAKES two numbers as input in binary form and results whether one input is greater, LESSER or equal to the other input. In a digital comparator, only 3 outputs are possible (i.e. A = B, A >B, A < B). Other than this, the output will be 0.

Right option is (a) 1

For explanation I would say: A comparator is a combinational CIRCUIT that takes two numbers as input in binary FORM and results WHETHER one input is greater, lesser or equal to the other input. Thus, there are two INPUTS required for a DIGITAL comparator (i.e. A & B).

The correct answer is (b) a – b

Explanation: A COMPARATOR is a COMBINATIONAL circuit that TAKES two numbers as input in binary form and RESULTS whether one input is greater, lesser or equal to the other input. In a digital comparator, only 3 outputs are possible (i.e. A = B, A > B, A < B). So, a – b is an INCORRECT option.

Right answer is (a) 1 circuit

Easiest explanation: A comparator is a combinational circuit that TAKES TWO numbers as input in binary form and results whether one input is greater, LESSER or EQUAL to the other input. Because, all the input is compared to each other, therefore it is possible only by using 1 circuit.

The CORRECT option is (a) 0011101

To explain I would SAY: The given BCD number 00101001 has three 1s. So, it can be REWRITTEN as 0000001-1, 0001000-8, 0010100-20 and after addition, we get 0011101 as OUTPUT.

Correct answer is (C) Mathematical puzzles

For explanation I would SAY: The REFLECTED binary code is also known as gray code because one digit reflected to the next bit. In Gray Code, EVERY sequence of successive bits differs by 1 bit only. Reflected binary codes were applied to mathematical puzzles before they became known to engineers.

The correct choice is (c) ERROR correction

Easiest EXPLANATION: Today, GRAY codes are widely used to FACILITATE error correction in digital communications such as digital terrestrial TELEVISION and some cable TV systems.

The correct answer is (d) Gray Code

Best EXPLANATION: The reflected BINARY code is also known as gray code because one digit reflected to the NEXT bit. In Gray Code, EVERY sequence of successive bits differs by 1 bit only.

Right option is (c) Only one DIGIT changes between COUNTS

To EXPLAIN I would say: The Gray code is more PRACTICAL to USE when coding the position of a rotating shaft because only one digit changes between counts that is reflected to the next count.

Right option is (a) With MSI IC circuits

To elaborate: One way to CONVERT BCD to binary USING the hardware APPROACH is MSI IC (i.e. MEDIUM scale integration) circuits.

Right ANSWER is (a) Discrete information

Easiest EXPLANATION: Code is a symbolic REPRESENTATION of discrete information. CODES can be anything like numbers, letter or words, written in terms of group of SYMBOLS.

Correct answer is (c) Converts DATA of one TYPE into another type

Explanation: A code CONVERTER is a LOGIC circuit that changes data presented in one type of BINARY code to another type of binary code.

Right choice is (c) EX-OR

Explanation: Exclusive-OR gates are ideal for CHECKING the PARITY of a BINARY number because they produce an output when the input has an odd number of 1’s. Therefore, an even-parity input to an EX-OR gate produces a low output, while an odd parity input produces a high output. While, in case of AND, it produces high output when all inputs are 1 ELSE low. Whereas, NAND, does the opposite, by producing low output when all inputs are 1 else high.

Correct answer is (a) Coded representation of a shaft’s mechanical position

The explanation is: GRAY code is useful because only one bit changes at a time, which is implemented easily in Coded representation of a shaft’s mechanical position. In Gray Code, EVERY SEQUENCE of SUCCESSIVE bits differs by 1 bit only.

The CORRECT option is (a) Indeterminate

Best EXPLANATION: Odd parity bit is 1 when the group of data bits consists of even number of 1s. So to make the group of data bits have odd number of 1s, 1 extra bit is added. If odd parity is used for ASCII error detection, the number of 0s PER 8-bit symbol is indeterminate because it is APPLICABLE only for 6-bit symbol.

Correct ANSWER is (b) Two-dimensional PARITY check

Best explanation: A single-bit ERROR can be detected by using two-dimensional parity check method. SINCE it converts the 4-bit number into 8-bit and COUNT the number of one’s.

The correct OPTION is (b) 1

Best explanation: The odd parity OUTPUT of decimal number 9 is 1 because the BCD number for 9 is 1001 and it has even number of 1’s.

Right ANSWER is (a) EVEN

For explanation I would say: The GIVEN BCD NUMBER 101011 has even priority because it has an even number of 1’s (i.e. 4).

The correct option is (a) 2

Easiest EXPLANATION: There are two types of PARITY BITS, namely even parity and odd parity. In even parity, a 1 bit is added in order to MAKE a group of data bits have even NUMBER of 1s. While, in odd parity, a 1 bit is added in order to make a group of data bits have odd number of 1s.

Right choice is (a) An ERROR detection is achieved by adding an extra BIT

Easy explanation: A simple form of error detection is achieved by adding an extra bit to the transmitted WORD. The additional bit is KNOWN as parity bits.

Right answer is (a) Simple parity check

Explanation: A parity checker is an error detection method used for the purpose of detecting ERRORS that may have been incorporated during transmission. Simple parity check method CONSISTS of just one REDUNDANT bit per DATA unit. It is again classified as even parity and odd parity.

The correct option is (d) Checksum

Easiest explanation: A checksum is an error DETECTION method used for the purpose of detecting errors that may have been incorporated during transmission. The checksum can be GENERATED simply by adding BITS. HENCE, ONE’s complement arithmetic uses checksum.

Right answer is (a) Hexadecimal 1-of-16

Easy explanation: A binary decoder is a combinational logic circuit that decodes binary information from n-inputs to a MAXIMUM of 2^n outputs. A TRUTH table with output COLUMNS numbered 0–15 may be for Hexadecimal 1-of-16. Because hexadecimal OCCUPIES less space in a SYSTEM.

Right option is (d) 4

The explanation: A binary decoder is a combinational LOGIC CIRCUIT which DECODES binary information from n-inputs to a maximum of 2^n outputs. Here, number of outputs = 16.

16 = 2^4 = 2^n. THUS, number of inputs is 4.

Correct answer is (a) By USING MSI IC circuits

Explanation: One way to convert BCD to binary using the hardware APPROACH is MSI (medium scale integration) IC circuits.

The correct CHOICE is (c) 128

To EXPLAIN: The possible outputs WOULD be: 2^n = 64 (Since n = 6 here).

Right answer is (a) 4

Explanation: A BINARY DECODER is a combinational logic circuit which decodes binary INFORMATION from n-inputs to a MAXIMUM of 2^n outputs. Therefore, for a BCD to decimal decoder, No. of inputs = 4 such that NUMBER of outputs is <= 2^n.

Correct ANSWER is (b) A LOW on all gate ENABLE INPUTS

To explain: A LOW on all gate enable inputs is necessary to operate a 1-line-to-16 line decoder because enable pins are USUALLY, active-low pins.

Correct option is (d) DECODER

The best EXPLANATION: A binary decoder is a combinational LOGIC circuit which decodes binary information from n-inputs to a MAXIMUM of 2^n outputs. Decoder converts the coded characters into our required data FORM.

Correct option is (d) 10

For EXPLANATION I would say: A binary decoder is a COMBINATIONAL logic circuit which decodes binary information from n-inputs to a maximum of 2^n outputs. A BCD to Decimal decoder has 10 number of outputs because the decimal DIGIT’s RANGE is from 0 to 9.

Right answer is (a) The higher value

To explain: An ENCODER is a combinational CIRCUIT encoding the information of 2^N input LINES to n output lines, THUS producing the binary equivalent of the input. If two inputs are active on a priority encoder, the input of higher value will be coded in the output.

The correct option is (B) Yes

Easy explanation: A multiplexer or MUX is a combination circuit that CONTAINS more than one input LINE, one OUTPUT line and more than one selection line. Whereas, an encoder is also considered a type of multiplexer but without a SINGLE output line and without any selection lines.

Correct option is (a) ENABLE

To explain: Such problems are resolved by using enable input, which BEHAVES as ACTIVE if it GETS 0 as input SINCE it is an active-low pin.

Correct answer is (b) 2^8

For explanation: An encoder is a COMBINATIONAL circuit encoding the information of 2^n INPUT lines to n OUTPUT lines, thus producing the binary equivalent of the input. There are 2^8 COMBINATIONS are possible for an 8-bit input encoder but out of which only 8 are used USING 3 output lines. It is a disadvantage of encoder.

The CORRECT option is (a) 3

To elaborate: An ENCODER is a COMBINATIONAL circuit ENCODING the information of 2^n input lines to n output lines, thus producing the binary equivalent of the input. Thus, in OCTAL to binary encoder there are8 (=2^3) inputs, thus 3 output lines.

Correct answer is (d) 4

Easiest explanation: An encoder is a COMBINATIONAL circuit ENCODING the information of 2^n input lines to n output lines, thus producing the binary equivalent of the input.

This is CLEAR from the diagram that it REQUIRES 4 OR GATES:

.