Unit 1 Data Representation

Question 1

How is:

Sound recorded

Answer 1

1. As an analogue wave
2. Converted into digital format
3. Done by Analogue to Digital converter(ADC)

Question 2

How is:

Sound measured

Answer 2

1. Sound wave is split through sampling
2. measurements are taken through wave height
3. This is done at regular intervals
4. stored in binary

Question 3

What is:

Sample rate

Answer 3

1. Sample rate is samples/second
2. Measured in Hz

Question 4

What is:

Bit depth

Answer 4

Number of bits defining each pixel

Question 5

What is:

Bit rate

Answer 5

data processed per second of sound

Question 6

Formula for size of a:

Sound file

Answer 6

bit rate * time

Question 7

Formula for an:

image

Answer 7

pixel resolution * colour depth * folder size

Question 8

What is:

Data about an image

Answer 8

Meta data

Question 9

What is:

meta data

Answer 9

information about a particular image

e.g. colour depth and pixel resolutio

Question 10

What is the use of:

Hexadecimal

Answer 10

easier to read than binary
MAC address is in hex

Question 11

How are:

Negative numbers stored

Answer 11

Through 2’s compliment
Do some practice
Some registers store negative numbers

Question 11

What is:

Overflow error

Answer 11

Where there are not enough bits to store a calculation, so data is lost

Question 12

How are:

Images created

Answer 12

Through a lot of individual pixels which have different colours by having a different shade of green, red and blue

Question 13

What is:

ASCII

Answer 13

• American Standard code for information interchange
• uses 7 bits
• stores 128 different characters
• new extended version is 8 bit

Question 14

What is:

Unicode

Answer 14

• stores all possible characters/keys on a keyboard
• over 65,000 storage capacity
• 16 bits

Question 15

What is a:

Binary shift

Answer 15

If all the 1s of a binary number are shifted left, the number doubles
Opposite applies as well

Question 16

What are the different:

Units for storage

Answer 16

Bit
Nibble (4bits)
Byte (2 nibbles)
Kibibyte (KiB) (1024 bytes)
Mebibyte (MiB) (1024 KiB)
Gibibyte (GiB) (1024 MiB)
Tebibyte (TiB) (1024 GiB)
Pebibyte (PiB) (1024 TiB)
Exbibyte (EiB) (1024 PiB)

Question 17

What is:

Compression

Answer 17

Reducing the size of a file

Question 18

What is:

Lossy compression

Answer 18

• Removing unnecessary data
• Can lead to a lower image quality
• e.g. decreasing an image resolution or removing sounds above 16500Hz

Question 19

What is:

Lossless compression

Answer 19

• Compression where no data is loss
• Works by using an algorithm which re-writes the data in a more effective way e.g. Run Length Encoding which re-uses data at specific intervals
• Original file can then be retreived by decoding the file algorithm

Question 20

What is:

Sample resolution

Answer 20

Number of bits used to describe the amplitude of a wave