CD

• When was the CD first released as a commercial format?


  In the early 1980s
• How is data stored on a CD?


  Data is stored as digital information read by a laser
• What process do writable CD drives use to transfer information to a CD-R?


  Writable CD drives use a laser
• How do commercial CDs differ from writable CDs in terms of data transfer?


  Commercial CDs use a moulding process to stamp the digital signal
• What is the process of converting analogue signals into digital information for CDs?


  Digital information is sampled and converted into binary data
• What do consumer players do with the digital information on a CD?


  They convert it back into an analogue signal
• When did CDs begin to become popular?


  In the late 1980s
• What event contributed to the rise in popularity of CDs in 1987?


  The release of the Beatles back-catalogue on CD
• How did the popularity of CDs affect the sales of vinyl and cassettes?


  Sales of vinyl and cassettes declined as people bought CDs
• What are the advantages of CDs over older formats?

  • Higher sound quality due to digital format
  • Digital-to-analogue conversion rate is high
  • No background noise
  • Not affected by dust or magnets
  • Minimal degradation over time
• What is the data storage specification for CDs as per the Red Book Standard?


  16 bit/44.1kHz
• What does Nyquist's Theorem state about sample rates?


  The sample rate should be twice the highest frequency captured
• What is the maximum frequency of human hearing that a sample rate of 44.1kHz can adequately capture?


  20kHz or 20,000Hz
• What are some disadvantages of CDs?


  CDs are fragile and can easily scratch
• What happens when a CD gets scratched?


  It can leave vast sections of the data unplayable
• When were CDs the most popular format for purchasing music?


  From the early 1990s through to the 2000s
• What has contributed to the decline in CD popularity?


  The rise of downloading music
• What are the differences between MP3 files and CDs?


  • CDs contain uncompressed audio
  • MP3 files are compressed audio
  • Streaming audio can also be compressed
  • CDs provide better audio quality
• What is likely to remain a place for in the future regarding audio formats?

  The better quality of CDs or an equivalent