Q.1

In an AHDL BCD to binary code converter, how is multiplication by 10 accomplished?

  • By using the shifting of bits
  • By using the library multiplication function
  • By using integer types
  • By using the multiplication operator
Q.2

What is the HDL key issue in the design of the MUX and DEMUX?

  • Having the MUX and DEMUX part of the library
  • Using the case statement in the process
  • Describing the functions
  • Assigning signals under certain conditions
Q.3

What type of device is shown in the given figure, and what inputs (A3,A2,A1,A0) are required to produce the output levels as shown?

  • A binary-to-decimal encoder; 0,1,1,1
  • A decimal-to-binary decoder; 1,1,1,0
  • A BCD-to-decimal decoder; 0,1,1,1
  • A decimal-to-BCD encoder; 1,1,1,0
Q.4

What are the outputs of a 7485 four-bit magnitude comparator when the inputs are A = 1001 and B = 1010?

  • A < B is 1
    A = B is 0
    A > B is 1
  • A < B is 0
    A = B is 1
    A > B is 0
  • A < B is 0
    A = B is 0
    A > B is 1
  • A < B is 1
    A = B is 0
    A > B is 0
Q.5

Why are control inputs included in an HDL magnitude comparator?

  • For cascading the chips
  • For control signal input
  • For signal control
  • For internal interconnections
Q.6

What are the outputs of a 7485 four-bit magnitude comparator when the inputs are A = 1001 and B = 1010?

  • A < B is 1
    A = B is 0
    A > B is 1
  • A < B is 0
    A = B is 1
    A > B is 0
  • A < B is 0
    A = B is 0
    A > B is 1
  • A < B is 1
    A = B is 0
    A > B is 0
Q.7

There appears to be a problem with a 7-segment display on a DMM sometimes skipping certain numbers. How would you test the display?

  • Remove the display unit and check each segment diode with an ohmmeter. Replace the defective segments.
  • Apply 5 V directly to each segment of the display and check for individual segment operation. Replace any segment that has voltage applied but is not lit.
  • Tie all of the segments together and connect to Vcc; the number 8 should appear on the display. Now check the display supply voltage to determine if the display is receiving the correct voltage.
  • Connect the DMM to a variable supply and very slowly increase the voltage, while observing for missing digits. Then check the segment voltage to determine whether the display or the display driver is bad.
Q.8

A 16-input multiplexer is to be used to perform parallel-to-serial data conversion. Which of the following counters would be required to provide the data select inputs?

  • MOD 8
  • MOD 16
  • MOD 4
  • MOD 2
Q.9

In most modern computers, the transfer of data takes place over a common set of connecting lines called a ________.

  • data bus
  • bus line
  • bus cable
  • data line
Q.10

What VHDL techniques are used to describe a priority encoder?

  • Integer outputs and priority coding
  • Signal outputs and priority coding
  • Tristate outputs and priority coding
  • Variables and priority coding
Q.11

What is the purpose of a decoder's inputs?

  • To allow the decoder to respond to the inputs to activate the correct output gate.
  • To disable the decoder outputs so that all outputs will be inactive.
  • To disable the inputs and activate all outputs.
  • To allow the decoder to respond to the inputs to activate the correct output gate, and to disable the inputs and activate all outputs.
Q.12

A breadboard-circuit design using a BCD-to-decimal decoder has a problem wherein the operation of the system is erratic. The technician uses his scope to examine the waveforms throughout the system and doesn't really see any problems. While he's scratching his head, what helpful advice can you offer him as to what might be wrong and what to do to correct the problem?

  • The decoder is thermally intermittent; replace it.
  • There is probably a bad connection on the wire wrap protoboard; recheck the wiring.
  • Glitches are probably the culprit; strobe the decoder.
  • The decoder is thermally intermittent and must be replaced; or there is probably a bad connection on the wire wrap protoboard, and the wiring must be rechecked.
Q.13

An octal-to-binary encoder has eight data inputs and encodes an output of ________ bits.

  • two
  • three
  • four
  • five
Q.14

Which is the decimal number for the BCD number, 10110110?

  • 182
  • 36
  • 116
  • 10110110 is not a valid BCD number.
Q.15

A 75154 1-of-16 decoder has 16 outputs and decodes an input of ________ bits.

  • two
  • three
  • four
  • six
Q.16

In an AHDL BCD to binary coded converter, multiplication by 10 is performed by ________.

  • a multiplication operator
  • shifting bits
  • a library function
  • a variable type
Q.17

What is an important attribute of the conditional signal assignment statement?

  • Its tristate outputs
  • Its sequential evaluation
  • Its use of library components
  • Its fast activation times
Q.18

Which statement best describes the given figure, and what is the function of the terminal labeled EN?

  • Quad two-input multiplexer. EN is the enable input, which requires an active LOW for the device to work.
  • Quad two-bit multiplier, EN is the active HIGH trigger.
  • Dual quad-input multiplexer, which requires an active LOW on the EN terminal for the device to work.
  • Quad two-input AND gate, which requires an active LOW on the EN input to enable all the gates.
Q.19

The circuit in Figure 9-8 is defective; data is not appearing on the output lines. A check with the scope shows data pulses on the serial data line and multiplex control lines, S0–S2; no parity error is indicated. A further check with a logic probe indicates that Vcc and ground appear to be present. What might be wrong with the circuit?

  • The demultiplexer may be bad.
  • The parity checker is defective.
  • The parity generator may be bad.
  • The parity checker is defective, or the parity generator may be bad.
Q.20

Which is the decimal number for the BCD number, 10110110?

  • 182
  • 36
  • 116
  • 10110110 is not a valid BCD number.
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