TEST I mid term

Question 1

1965
–
Moore’s Law

Answer 1

which states that the number
of transistors on a chip doubles about every two
years, the law is born when Intel’s Gordon Moore
made a prediction about the semiconductor
business that still holds true today

Question 2

analog Quantities

Answer 2

Most natural quantities that we see are 
analog
and vary 
continuously. Analog systems can generally handle higher 
power than digital systems

Question 3

What kinds of data do we need to represent?

Answer 3

Logical
–
true, false
–
Numbers
–
signed, unsigned, integers, floating point,
complex, rational, irrational, ...
–
Text
–
characters, strings, ...
–
Instructions
–
Images
–
pixels, colors, shapes, ...
–
Sound

Question 4

Data type:

Answer 4

representation
and
operations
within the computer

Question 5

Analog and Digital Systems combination

Answer 5

Many systems use a mix of analog and digital electronics to
take advantage of each technology. A typical CD player
accepts digital data from the CD drive and converts it to an
analog signal for amplification

Question 6

Binary Digits and Logic Levels

Answer 6

In binary, a single number is 
called a bit (for binary digit). A 
bit can have the value of either 
a 0 or a 1, depending on if the 
voltage is HIGH or LOW

Question 7

Digital Waveforms

Answer 7

Digital waveforms change between the LOW and HIGH
levels. A positive going pulse is one that goes from a
normally LOW logic level to a HIGH level and then back
again. Digital waveforms are made up of a series of pulses

Question 8

Pulse Definitions

Answer 8

Actual pulses are not ideal but are described by the rise time,
fall time, amplitude, and other characteristics

Question 9

how many states does a collection on n bits have

Answer 9

A collection of n bits has 2n

possible states

Question 10

Timing Diagrams

Answer 10

A timing diagram is used to show the relationship between

two or more digital waveform

Question 11

Basic Logic Functions

Answer 11

AND - True only if all
input conditions
are true.
OR- true only one or more input conditions are true
NOT- indicates the opposite of a condition

Question 12

Examples of Basic System Functions

Answer 12

• The comparison function
• Basic arithmetic functions
• The encoding function
• The decoding function

Question 13

What are the types of integrated circuits

Answer 13

DIP chips and surface mount chips

Question 14

What is PLC

Answer 14

Programmable logic devices (PLDs) are an alternative to
fixed function devices. The logic can be programmed for a
specific purpose. In general, they cost less and use less
board space
than
fixed function devices.

Question 15

Gate

Answer 15

A logic circuit that performs a basic logic

operations such as AND or OR.

Question 16

Fixed -function

logic

Answer 16

A category of digital integrated circuits having

functions that cannot be altered

Question 17

Compared to analog systems, digital systems

a. are less prone to noise
b. can represent an infinite number of values
c. can handle much higher power
d. all of the above

Answer 17

are less prone to noise

Question 18

The number of values that can be assigned to a bit are

a. one
b. two
c. three
d. ten

Answer 18

2

Question 19

The time measurement between the 50% point on the
leading edge of a pulse to the 50% point on the trailing edge
of the pulse is called the
a. rise time
b. fall time
c. period
d. pulse width

Answer 19

pulse Width

Question 20

The time measurement between the 90% point on the
trailing edge of a pulse to the 10% point on the trailing edge of
the pulse is called the
a. rise time
b. fall time
c. period
d. pulse width

Answer 20

fall time

Question 21

The reciprocal of the frequency of a clock signal is the

a. rise time
b. fall time
c. period
d. pulse width

Answer 21

period

Question 22

If the period of a clock signal is 500ps, the frequency is

a. 20 MHz
b. 200 MHz
c. 2 GHz
d. 20 GHz

Answer 22

2GHz

Question 23

AND, OR, and NOT gates can be used to form

a. storage devices
b. comparators
c. data selectors
d. all of the above

Answer 23

• storage devices
• comparators
• data selectors

Question 24

A shift register is an example of a

a. storage device
b. comparator
c. data selector
d. counter

Answer 24

storage device

Question 25

A device that is used to switch one of several input lines to 
a single output line is called a 
a. comparator
b. decoder
c. counter
d. multiplexer

Answer 25

multiplexer

Question 26

For most digital work, an oscilloscope should be coupled 
to the signal using
a. ac coupling
b. dc coupling
c. GND coupling
d. none of the abov

Answer 26

dc coupling

Question 27

point
number

Answer 27

A number representation based on scientific
notation in which the number consists of an
exponent and a mantissa

Question 28

Hexadecimal

Answer 28

A number system with a base of 16

Question 29

Octal

Answer 29

A number system with a base of 8

Question 30

BCD

Answer 30

Binary coded decimal; a digital code in which each
of the decimal digits, 0 through 9, is represented by
a group of four bits.

Question 31

Alphanumeri

Answer 31

Consisting of numerals, letters, and other

characters

Question 32

ASCII

Answer 32

American Standard Code for Information
Interchange; the most widely used alphanumeric
code.

Question 33

Parity

Answer 33

In relation to binary codes, the condition of
evenness or oddness in the number of 1s in a code
group.

Question 34

Cyclic
redundancy
check (CRC)

Answer 34

A type of error detection code.

Question 35

The Inverter

Answer 35

The inverter performs the Boolean NOT operation. When the input is LOW, the output is HIGH; when the input is HIGH, the output is LOW.

-
the Boolean expression for an inverter is X = A.

Question 36

The AND Gate

shown with a” .”

Answer 36

The AND gate produces a HIGH output when all inputs are HIGH; otherwise, the output is LOW. For a 2-input gate, the truth table is

Thus, the AND operation is written as X = A .B or X = AB.

Question 37

uses of the And gate

Answer 37

The AND operation is used in computer programming as a selective mask. If you want to retain certain bits of a binary number but reset the other bits to 0, you could set a mask with 1’s in the position of the retained bits.

Question 38

The OR Gate

shown with a +

Answer 38

The OR gate produces a HIGH output if any input is HIGH; if all inputs are LOW, the output is LOW. For a 2-input gate, the truth table is

Thus, the OR operation is written as X = A + B.

Question 39

The NAND Gate

shown with an over bar covering the expression.

Answer 39

The NAND gate produces a LOW output when all inputs are HIGH; otherwise, the output is HIGH. For a 2-input gate, the truth table is

Thus, the NAND operation is written as X = A .B (Alternatively, X =AB.)

Question 40

The NOR Gate

The NOR operation is shown with a plus sign (+) between the variables and an overbar covering them

Answer 40

The NOR gate produces a LOW output if any input is HIGH; if all inputs are HIGH, the output is LOW. For a 2-input gate, the truth table is

Thus, the NOR operation is written as X = A + B.

Question 41

The XOR Gate

The XOR operation is written as X = AB + AB.

Answer 41

The XOR gate produces a HIGH output only when both inputs are at opposite logic levels. The truth table is

Question 42

The XNOR Gate

X = AB + AB

Answer 42

The XNOR gate produces a HIGH output only when both inputs are at the same logic level.

Question 43

Programmable Logic Device (PLD)

Answer 43

A Programmable Logic Device (PLD) can be programmed to implement logic. There are various technologies available for PLDs. Many use an internal array of AND gates to form logic terms. Many PLDs can be programmed multiple times.