Digital Electronics-Code Converts and Multiplexers
Digital Electronics-Code Converts and Multiplexers
21. Why is a demultiplexer called a data distributor?
- The input will be distributed to one of the outputs.
- One of the inputs will be selected for the output.
- The output will be distributed to one of the inputs.
22. What is the status of the inputs S0, S1, and S2 of the 74151 eight-line multiplexer in order for the output Y to be a copy of input I5?
- S0 = 0, S1 = 1, S2 = 0
- S0 = 0, S1 = 0, S2 = 1
- S0 = 1, S1 = 1, S2 = 0
- S0 = 1, S1 = 0, S2 = 1
23. One way to convert BCD to binary using the hardware approach is:
- with MSI IC circuits
- with a keyboard encoder
- with an ALU
- UART
24. A microcontroller differs from a microprocessor in that it has several ________ ports and ________ built into its architecture, making it better suited for ________ applications.
- communication, PROMs, control
- parallel, logic gates, processing
- input/output, memory, control
- data, memory, decoding
25. 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.
26. Why is the Gray code more practical to use when coding the position of a rotating shaft?
- All digits change between counts.
- Two digits change between counts.
- Only one digit changes between counts.
27. For the following conditions on a 7485 magnitude comparator, what will be the state of each of the three outputs?
A0 = 0 B0 = 1 IA < B = 0
A1 = 1 B1 = 0 IA = B = 1
A2 = 1 B2 = 0 IA > B = 0
A3 = 0 B3 = 0
A0 = 0 B0 = 1 IA < B = 0
A1 = 1 B1 = 0 IA = B = 1
A2 = 1 B2 = 0 IA > B = 0
A3 = 0 B3 = 0
- A = B = 0, A < B = 0, A > B = 1
- A = B = 0, A < B = 1, A > B = 0
- A = B = 1, A < B = 0, A > B = 0
- A = B = 0, A < B = 0, A > B = 0
28. When two or more inputs are active simultaneously, the process is called:
- first-in, first-out processing
- priority encoding
- ripple blanking
- first-in, first-out processing or priority encoding
29. A binary code that progresses such that only one bit changes between two successive codes is:
- nine's-complement code
- 8421 code
- excess-3 code
- Gray code
30. Which of the following is not a weighted value positional numbering system:
- hexadecimal
- binary-coded decimal
- binary
- octal