Encoder and Decoder Question & Answers November 22, 2021 By WatElectronics This article lists 100 Encoder and Decoder MCQs for engineering students. All the Encoder and Decoder Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up their fundamentals on Encoder and Decoder. The field of digital communications involves digital communication using 0’s and 1’s. For secure communication to take place the data need to be encrypted and decrypted using securing techniques. Encoders and Decoders are used for encrypting data at the sender's end and decrypting data at the receiver's end. An encoder and decoder in the digital world is an IC technology designed with multiple electronic components and gates. The input lines of both encoder and decoder are enabled when the input enable pin of both the ICs are enabled. HC148 and H12E are a few examples of encoders. Whereas the examples of decoders IC include 74138, IC 74139, MT8870C, MT8870C-1, and DTMF. Encoders benefit in terms of enhanced resolution, compact in area, and uses of digital technology. Decoders benefit in terms of taking single input, having code converters, and having memory systems with high performance. Decoders are used in 7segment display, data multiplexing and port mapped I/O. Encoders are used in RF communication, remote controller, and radio technology. 1). Encoder in digital circuits is similar to ___ components in digital world? Multiplexers De-multiplexer Adders Subtractors None Hint 2). De-coder in digital circuits is similar to ___ components in digital world? Multiplexers De-multiplexer Adders Subtractors None Hint Read more about Demultiplexer. 3). How many inputs do an encoder have? N 2^N 1/N 2^-N None Hint 4). How many outputs do an encoder have? N 2^N 1/N 2^-N None Hint 5). A 4bit encoder has ____ number of inputs? 1 2 3 4 None Hint 6). Which of the following is the output “A,B” for an encoder with 4bits “Y1,Y2,Y3,Y4” as “ 0001”? 00 01 10 11 None Hint 7). Which of the following is the output “A,B” for an encoder with 4bits “Y1,Y2,Y3,Y4” as “ 0010”? 00 01 10 11 None Hint 8). Which of the following is the output “A,B” for an encoder with 4bits “Y1,Y2,Y3,Y4” as “ 0100”? 00 01 10 11 None Hint 9). Which of the following is the output “A,B” for an encoder with 4bits “Y1,Y2,Y3,Y4” as “ 1000”? 00 01 10 11 None Hint 10). A binary encoder is defined to be dual of ____? Multiplexer Full adder Full subtractor Binary decoder None Hint 11). A 4 to 2 encoder has ___ number of inputs? 2 3 4 1 None Hint 12). A 4 to 2 encoder has ___ number of outputs? 2 3 4 1 None Hint 13). A 8 to 3 encoder has ____ number of inputs? 3 1 8 2 None Hint 14). A 8 to 3 encoder has ____ number of outputs? 3 1 8 2 None Hint 15). A 4 to 2 encoder requires ___ number of logic gates? 2 3 4 5 None Hint 16). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00000000”? XXX 000 001 010 None Hint 17). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00000001”? XXX 000 001 010 None Hint 18). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00000010”? XXX 000 001 010 None Hint 19). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00000100”? XXX 000 001 010 None Hint 20). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00001000”? 011 100 101 110 None Hint 21). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00010000”? 011 100 101 110 None Hint 22). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “00100000”? 011 100 101 110 None Hint 23). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “01000000”? 011 100 101 110 None Hint 24). Which of the following is the output for 8 to 3 type encoder for input D [7] to D [0] “10000000”? 011 100 101 111 None Hint Read more about Gates. 25). An encoder uses ____ in IC technology? Active components Gates Electronic components All the above None Hint Encoder and Decoder Interview Questions and Answers 26). An encoder generates ___ type code on each input? Hexa Binary Octal ASCII None Hint Read more about Binary. 27). Which of the following pin of encoders IC defines that encoder is in active state? Input Output Enable All the above None Hint 28). Which of the following are the examples of encoders? MT8870C/MT8870C-1 DTMF HC 148 H12E Both b and c None Hint 29). How many types of conversion do an encoder performs? 2 3 4 1 None Hint 30). A HC148 type IC encoder has ___ number of pins? 8 12 16 18 None Hint 31). How many address pins are present in an HC148 type IC encoder? 8 12 16 20 None Hint 32). How many data pins are present in an HC148 type IC encoder? 8 12 16 20 None Hint 33). Which of the following encoder is used for RF communication? MT8870C/MT8870C-1 DTMF HC 148 H12E Both b and c None Hint 34). Which of the following is converted from parallel to serial in HC 148 IC encoder? Address Data Clock Triggers None Hint 35). How many words can a H12E type encoder transmits in a time? 2 3 4 5 None Hint 36). Which of following pin blocks the further transmission of words in an H12E IC encoder? CLK RST GND !TE None Hint 37). Which of the following are the features provided by H12E IC encoder? Requires input voltage of 2.4 to 12 volts CMOS technology Has built-in based oscillator All the above None Hint 38). Which of the following are the applications of H12E IC encoder? RF communication Remote controller Radio technology All the above None Hint 39). A HC148 type IC encoder has ____ number of input pins? 8 3 4 5 None Hint 40). A HC148 type IC encoder has ____ number of output pins? 8 3 4 2 None Hint 41). A HC148 type IC encoder is a ____ encoder? 1to2 2to4 4to1 8to3 None Hint 42). An H12E encoder is a ______ encoder? Holtek Priority Dual All the above None Hint 43). A 5 by 32 decoder circuit is implemented using ____ number of decoder? 5 4 3 2 None Hint Read more about Priority Encoder. 44). Which of the following is the voltage rage of HC148 IC type encoder? 2V to 6V 5V to 8V 1V to 2.5V 10V to 15V None Hint 45). Which of the following is not an encoder? 4to2 8 to 3 16 to 4 5 to 32 None Hint 46). Which of the following is not an decoder? 4to2 3 to 8 4 to 16 5 to 32 None Hint 47). Which of the following technologies are used for developing an encoder? Mechanical Magnetic Resistance All the above None Hint 48). Which of the following components are used while developing encoders? PCB’s Code disk Photo detector All the above None Hint 49). Which of the following are the advantages of an encoder? Enhance resolution Compact Digital technology All the above None Hint 50). Which of the following are the disadvantages of an encoder? Fragile components Fairley complicated Glitches All the above None Hint Encoder and Decoder Important Questions for Interviews 51). A decoder has _____ number of inputs? 2 n 2^n 2N None Hint 52). A decoder has __ number of outputs? 2 n 2^n 2N None Hint 53). Which of the following are the applications of decoder? 7segment display Data multiplexing Port mapped I/O All the above None Hint 54). A binary decoder can be synthesized using ______? Verilog VHDL C Both a and b None Hint 55). A 1 to n type decoder has ___ number of inputs? 1 N 2^n 2n None Hint 56). A 1 to n type decoder has ___ number of outputs? 1 N 2^n 2n None Hint 57). A 3 to 8 decoder has ___ number of inputs? 3 8 2^3 2*3 None Hint 58). A 3 to 8 decoder has ___ number of outputs? 3 8 2^6 2*8 None Hint 59). Which of the following are the examples of decoder? 3 to 8 BCD to decimal De-multiplexer All the above None Hint 60). A 2 to 4 decoder requires ___ number of logic gates to represent output? 4 3 2 6 None Hint 61). Which of the following is the output ‘Y3,Y2,Y1,Y0’ for 2 to 4 decoder with enable pin “0” and inputs A,B is ‘X,X’? 0000 0001 0010 0100 None Hint 62). Which of the following is the output ‘Y3,Y2,Y1,Y0’ for 2 to 4 decoder with enable pin “1” and inputs A,B is ‘00’? 0000 0001 0010 0100 None Hint 63). Which of the following is the output ‘Y3,Y2,Y1,Y0’ for 2 to 4 decoder with enable pin “1” and inputs A,B is ‘01’? 0000 0001 0010 0100 None Hint 64). Which of the following is the output ‘Y3,Y2,Y1,Y0’ for 2 to 4 decoder with enable pin “1” and inputs A,B is ‘10’? 0000 0001 0010 0100 None Hint 65). Which of the following is the output ‘Y3,Y2,Y1,Y0’ for 2 to 4 decoder with enable pin “1” and inputs A,B is ‘11’? 0000 0001 0010 1000 None Hint 66). Which of the following are the examples of decoders? IC 74138 IC 74139 MT8870C All the above None Hint 67). A MT8870C type decoder uses ___ type of technique for filtering data? Inductor Capacitor Resistor All the above None Hint 68). How much frequency of clock do a MT8870 type decoder uses for operation? 3.57 MHz 4MHz 2MHz 2.5 MHz None Hint 69). A MT8870 IC type decoder is of ___ pins? 4 12 16 18 None Hint 70). A HT9170B decoder is integrated with ___ type of receiver? Single tone Dual tone Dual tone multi frequency All the above None Hint 71). A HT9170B IC has ____ number of pins? 4 5 6 18 None Hint 72). Which of the following is the frequency of HT9170B IC? 3.5MHz 3.8MHz 3.2MHz 3MHz None Hint 73). How many data pins are present in a HT9170B IC? 2 1 3 4 None Hint 74). Which of the following decoder forms 4 to 16 decoder? 3 to 8 2 to 4 3 to 5 All the above None Hint 75). Which of the following is number of decoders required for implementing 4 to 16 line decoder? 16/8 8/6 8/4 4/8 None Hint Encoder and Decoder Quiz Questions and Answers. 76). How many logic gates are required for 4 to 16 line decoder? 8 12 16 20 None Hint 77). Which of the following is the formula for calculating number of decoders required for implementing lower order decoder? M1/m2 M2/m1 M1*m2 M2-M1 None Hint 78.) Which of the following is the output of 3to8 type decoder when input is 0,XXX where ABC are inputs? Abar *B bar* C bar A * B* C A+B bar +C A bar +B +C None Hint 79). Which of the following is the output of 3to8 type decoder when input is 1,000 where ABC are inputs? Abar *B bar* C A * B* C A+B bar +C A bar +B +C None Hint 80). Which of the following is the output of 3to8 type decoder when input is 1,001 where ABC are inputs? Abar *B * C A * B* C A+B bar +C A bar +B +C None Hint 81). Which of the following is the output of 3to8 type decoder when input is 1,010 where ABC are inputs? Abar *B * C bar A * B* C A+B bar +C A bar +B +C None Hint 82). Which of the following is the output of 3to8 type decoder when input is 1,011 where ABC are inputs? Abar *B * C A * B* C A+B bar +C A bar +B +C None Hint 83). Which of the following is the output of 3to8 type decoder when input is 1,100? A *B bar * C bar A * B* C A+B bar +C A bar +B +C None Hint 84). Which of the following is the output of 3to8 type decoder when input is 1,101 where ABC are inputs? A *B bar * C A * B* C A+B bar +C A bar +B +C None Hint 85). Which of the following is the output of 3to8 type decoder when input is 1,110 where ABC are inputs? A *B * C bar A * B* C A+B bar +C A bar +B +C None Hint 86). Which of the following is the output of 3to8 type decoder when input is 1,111 where ABC are inputs? A *B * C bar A * B* C A+B bar +C A bar +B +C None Hint 87). How many NOT gates are required in a 4to16 based decoder? 2 4 6 8 None Hint 88). How many NAND gates are required in a 4to16 based decoder? 2 4 8 16 None Hint 89). How many input digits do a Binary type BCD decoder requires? 2 4 8 12 None Hint Read more about BCD. 90). How many outputs do BCD decoder has? 2 1 5 10 None Hint 91). A BCD decoder is also called as ______? 1 to 10 decoder 1 to 9 decoder 0 to 9 decoder All the above None Hint 92). Which of the following decoder is used in cpu’s memory? Address decoder Instruction decoder Program decoder All the above None Hint 93). Which of the following decoder is used in control unit of CPU? Address decoder Instruction decoder Program decoder All the above None 94). Which of the following decoder activates ALU of CPU? Address decoder Instruction decoder Program decoder All the above None Hint 95). Which of the following type of decoders are used in place of PLDs? Address decoder Instruction decoder Program decoder All the above None Hint 96). Which of the following decoder is used by microprocessor for selecting multiple bytes from memory at a time? Address decoder Instruction decoder Program decoder All the above None Hint 97). Which of the following are the advantages of decoders? Takes single input Has code converters Has memory systems with high performance All the above None Hint 98). Which of the following are the disadvantages of decoders? Provides logic 0 as out output on open connection Susceptibility to dust Interference with direct light All the above None Hint 99). Which of the following is the characteristic of encoder? Original input message is applied Simple in operation OR gate is used All the above None Hint 100). Which of the following is the characteristic of decoder? Coded based binary input is applied Complex in operation AND and NOT gate is used All the above None Hint Time's up
