3.5 Flashcards Preview

AS Computing - OW > 3.5 > Flashcards

Flashcards in 3.5 Deck (63)
Loading flashcards...
1

What is a natural number? (N)

is a whole number that is used in counting (0,1,2,3,4,5,6,7,8,9)

2

What is a rational number? (Q)

any value that can be expressed as a ratio or a fraction. Includes integer values e.g. 3/1, 6.74/1000

3

What is an irrational number? (Q')

a value that cannot be expressed as a fraction and has an endless series of non-repeating digits. e.g. pi - 3.1415

4

What is an integer number? (Z)

a whole number that could be positive or negative e.g. -2,-1,0,1,2

5

What is a real number? (R)

any number that is natural, rational or irrational. The set of real numbers is the set of all possible real-world quantities.

6

What is an ordinal number?

to describe the numerical position of the object e.g. 1st, 2nd, 3rd

7

What are natural and real numbers for?

natural numbers - for counting
real numbers - for measurement

8

How do you find the number of bits in binary?

2^{n-1}

9

How many bits in 1 byte

8 bits

10

Fill the gaps
nibble, ____, byte, __, MB, __, TB, __

Nibble, bite, byte KB, MB, GB, TB, PB

11

What does ASCII stand for?

American Standard Code for Information Interchange

12

Computers use Two's complement to represent what two numbers?

Positive & negative numbers

13

What is fixed point binary?

There is a fixed number of digits after the decimal point

14

What is fixed point binary used for?

For displaying decimal numbers (this makes the number more exact)

15

One advantage of fixed point binary?

it stores the number accurately

16

One negative of fixed point binary?

Cannot represent wide range of numbers in the same number of bits e.g. 4000 or 0.0001

17

What is the difference between signed and unsigned binary?

Signed binary means that the item can hold positive or negative values. Unsigned binary doesn't distinguish between positive and negative values.

18

In unsigned binary, what is the minimum & maximum value for a given number of bits (n)?

2^{n-1} & 0

19

What is Ascii & Unicode?

Ascii uses an 8-bit encoding while Unicode uses a variable bit encoding.
Unicode is standardized while ASCII isn't.
Unicode represents most written languages in the world while ASCII does not.

20

Why is error checking used?

because bits can change during transmission because of interference

21

What are the 3 forms of error checking & correction?

- Parity bits
- Majority voting
- Check digits

22

What is parity bits?

a bit which acts as a check on a set of binary values, calculated in such a way that the number of 1s in the set plus the parity bit should always be even (or occasionally, should always be odd).

23

What is majority voting?

it selects put error & takes the majority to correct the error
data = 1011
transmission = 111 000 111 111
received = 101 001 110 111

24

What is Metadata?

'data about data'
e.g. file name, date created, resolution, colour depth, creator

25

What are the two forms sound is stored in?

Analogue = infinite amount of binary

Digital = binary which computers understand

26

How do we convert analogue to digital?

We use a ADC (analogue to digital converter)

27

What is the ADC process?

Sound waves --> electrical voltage --> binary data

28

How do we convert digital to analogue?

We use a DAC (digital to analogue converter)

29

What is the DAC process?

binary data --> electrical voltage --> sound waves

30

If you have a higher sampling rate you get better _______

quality