Lecture 1

Question 1

Digit

Answer 1

Any of the Arabic figures of 1 through 9 and 0

Any of the symbols of other number systems, as 0 or 1 in binary

Question 2

Digital

Answer 2

Implies that all values in the system are fully represented by a series of digits

Of, relating to, or using data in the form of numerical digits (image)

Involving or using numerical digits expressed in a scale of notation, usually in the binary system, to represent discretely all variables occurring in a problem

Question 3

Analog

Answer 3

Of or relating to a mechanism that represents data by measurement of a continuous physical variable, as voltage or pressure

Question 4

The world is ____

Answer 4

Analog

Question 5

All analog observations have ____ possibilities

Answer 5

Infinite

Question 6

____ values simplify to a discrete or finite realm

Answer 6

Digital

Limited set of values for an observation

Question 7

Creating a digital signal from an analog signal

Answer 7

Quantize the analog signal, rounding all continuous values to the closest integer

Question 8

Digital, discrete-time signal

Answer 8

May be produced by an analog-to-digital converter (ADC)

Question 9

Digital systems

Answer 9

Inputs and outputs are both digital, discrete-time signals

Represents information with discrete-valued variables, variables with a finite number of distinct values

Question 10

Why use digital signals at all?

Answer 10

So that signal processing can be implemented on a digital computer (operate on 1’s and 0’s)

Digital signals are more immune to noise interference than their analog counterparts

Question 11

Disadvantages of digital signals

Answer 11

Reduces accuracy, adds additional components (ADC)

Question 12

Digital systems advantages

Answer 12

Building blocks are simple (1’s and 0’s)

Designer’s challenge is to combine these simple blocks into complicated systems

Microprocessor is an example of a digital system that is too complex to understand all at once

Question 13

Advances in microprocessors have:

Answer 13

Made cell phones and internet possible

Vastly improved medicine

Question 14

Managing complexity

Answer 14

Abstraction, discipline, and the 3-Y’s (hierarchy, modularity, regularity)

Question 15

Abstraction

Answer 15

Hiding details when they are not important

Question 16

The lowest abstraction level

Answer 16

Physics (motion of electrons)

Question 17

Behavior of electrons is determined by

Answer 17

Quantum mechanics and Maxwell’s equations

Question 18

Our system is constructed from ____ such as transistors (once, vacuum tubes)

Answer 18

Electronic devices

Question 19

Terminals

Answer 19

Well-defined connection points in devices

Can be modeled by the relationship between voltage and current as measured at each terminal

Question 20

Device level

Answer 20

Can ignore individual electrons

Transistors, diodes

Question 21

Analog circuits level

Answer 21

Devices are assembled to create components such as Amplifiers, filters

Input and output a continuous range of voltages

Question 22

Digital circuits level

Answer 22

AND gates, NOT gates

Restrict the voltages to discrete ranges, which we use to indicate 0 and 1

Question 23

Logic level

Answer 23

Adders, memories

Question 24

Micro-architecture level

Answer 24

Datapaths, controllers

Combining logic elements to execute the instructions defined by the architecture

Question 25

Architecture level

Answer 25

Instructions, registers Describes a computer from the programmer’s perspective

Question 26

Operation systems level

Answer 26

Device drivers Handles low-level details such as accessing a hard drive or managing memory

Question 27

Application software level

Answer 27

Programs Uses these facilities provided by the operating system to solve a problem for the user

Question 28

Abstraction levels

Answer 28

``` Application software Operation systems Architecture Micro-architecture Logic Digital circuits Analog circuits Devices Physics ```

Question 29

Discipline

Answer 29

The act of intentionally restricting your design choices so that you can work more productively at a higher level of abstraction Digital circuits

Question 30

Hierarchy

Answer 30

Dividing a system into modules, then further subdividing each of these modules until the pieces are easy to understand Breaking up into components, and describing lower-level components in detail

Question 31

Modularity

Answer 31

Giving modules well-defined functions and interfaces, so that they connect together easily without unanticipated side effects Dictates that there should be no side effects

Question 32

Regularity

Answer 32

Ensuring uniformity among modules so that common modules can be reused many times, reducing the number of distinct modules that must be designed Teaches that interchangeable parts are a good idea

Question 33

Charles Babbage’s Analytical Engine

Answer 33

1834-71 Mechanical computer that used variables with 10 discrete values Used gears with 10 positions labeled 0 through 9 Each row in the engine processes one digit 25 rows of gears, so 25-digit precision

Question 34

Binary representation

Answer 34

High voltage - 1 Low voltage - 0 Most electronic computers use this because its easier to distinguish between 2 voltages than 10

Question 35

A binary variable conveys...

Answer 35

1 bit of information

Question 36

Bit

Answer 36

Short for binary digit

Question 37

A continuous signal theoretically contains ___ amount of information

Answer 37

Infinite

Question 38

Boolean logic

Answer 38

Created by George Boole (1815-64) TRUE (1, HIGH) or FALSE (0, LOW)

Question 39

Digital abstraction

Answer 39

Allows digital designers to focus on 1’s and 0’s, ignoring whether the Boolean variables are physically represented by: specific voltages, rotating gears, hydraulic fluid levels

Question 40

A programmer can work without needing to know the intimate details of the ____

Answer 40

Computer hardware (HW) Understanding these HW details allows the programmer to optimize the software (SW) better for that specific compiler

Question 41

An individual bit carrier very little information

Answer 41

We use number systems to group bits together to represent numbers Groups of bits can also represent letters and programs

Question 42

Supply voltage

Answer 42

The highest voltage comes from the power supply (Vdd)

Question 43

The lowest voltage in the system is ___

Answer 43

0V (ground or GND)

Question 44

In 70’s-80’s tech, Vdd was

Answer 44

5V

Question 45

As chips have progressed to smaller transistors, Vdd has dropped to

Answer 45

3.3V, 2.5V, 1.8V, 1.5V, 1.2V, or lower to save power and avoid overloading the transistors

Question 46

The mapping of a continuous variable onto a discrete binary variable is done by defining

Answer 46

Logic levels

Question 47

Defining logic levels

Answer 47

1st gate - driver 2nd gate - receiver Output of driver connected to input of receiver Driver produces a 0 output in range of 0 to Vol or a high output in range 0 to Voh to Vdd

Question 48

If the receiver gets an input in the range 0 to Vil

Answer 48

Input LOW

Question 49

If the receiver gets an input in the range Vih to Vdd

Answer 49

Input HIGH

Question 50

If, due to noise or faults, the receiver’s input falls in the forbidden zone, the behavior of the gate is

Answer 50

Unpredictable

Question 51

Forbidden zone

Answer 51

Between Vil and Vih

Question 52

For output of driver to be correctly interpreted at input of receiver, we must choose...

Answer 52

Vol < Vil and Voh > Vih

Question 53

Noise margin

Answer 53

Amount of noise that could be added to a worst-case output such that the signal can still be interpreted as a valid input