Topic 2

• Why do we use hexadecimal?

  They are:

  • Easier read
  • Easier to write
  • Easier to remember
• What is the problem with ASCII?

  7 bits is not enough to represent all letters and symbols worldwide
• What is a better alternative to ASCII and why?


  Unicode

  • It can store more characters than ASCII can
• What factors affect the file size of an image?

  Resolution and Colour Depth
• What are the byte sizes in order?

  Bit,Nibble,Byte,Kibibyte,Mebibyte,Gibibyte,Tebibyte
• How do we convert analogue into digital sound?

  • Analogue sound waves are pitched up
  • Sound waves are sampled at regular intervals using an ADC and given binary values
  • Data can be viewed on a computer to either edit or played through a speaker
• What is the normal sample rate of a file?


  41,600
• What type of files would we use Lossy Compression on?

  We would use them on:

  • Sound
  • images
  • video
• What type of files would we use Lossless compression on?

  Text documents
• What are the aspects of Lossy compression?

  They:

  • Reduce the file's transmission time
  • Reduce internet traffic and collisions
  • Irreversible data loss
• What are the aspects of lossless compression?

  They:

  • Preserve their quality
  • Reversible data loss
  • Less significant reduction in file size