Unit 2: Data Representation

Numbers
1. Denary
  1. base 10: normal
2. hexadecimal
  1. base 16
    1. 0-9, A-F
  2. represents 4 bits per digit
3. Binary
  1. base 2
    1. 1 or 0
    2. on or off
  2. each digit represents a bit
images
1. bitmap
  1. image stored as a series of values per pixel
    1. Pixel is the smallest addressable value in an image
  2. arranged as a grid
  3. the resolution shows the number of pixels
2. vector
  1. images drawn to a formula
  2. rescaleing doesn't damage image quality
3. colour
  1. displayed as different binary digits
  2. colour depth is the number of bits used to display a colour of a single pixel in a bitmap
    1. the higher the colour depth, the more available colours
Units
1. bit
  1. 1 or 0
2. byte
  1. 8 bits
3. nibble
  1. 4 bits
4. kilobyte
  1. 1024 bytes
5. Megabytes
  1. 1024 kilobytes
6. gigabyte
  1. 1024 megabytes
7. terabyte
  1. 1024gigabytes
8. petabyte
characters
1. unicode
  1. 16 bits
    1. 65,536 characters approx.
  2. allows many more characters
  3. takes more space
2. ASCII
  1. American Standard Code for Information Interchange
  2. 7 bit character set
    1. 128 characters
    2. extended ASCII contains 8 bits
      1. 256 characters
  3. assigns a table of characters with unique binary values
sound
1. digital
  1. the way in which computers read sound
  2. sampling
    1. creates representation of original values by measuring specific values
    2. sample rate: times per second the sound wave is measured
      1. normal rate is around 44KHZ
2. analogue
  1. continuously changing wave
  2. natural sound

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Unit 2: Data Representation

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