Task 1

What is an audio made of?

INTRODUCTION

  • Audio signal is an electrical signal that represents a sound.
  • Sound is a variation in the instantaneous air pressure .The variations are of air pressure above and below average (barometric) air pressure.
  • Audio is an electrical (usually voltage) waveform that is analogous to the sound pressure waveform.
  • Audio signals are synthesized by a transducer such as a microphone which converts the sound pressure variations into voltage variations.
  • A higher voltage represents a higher pressure, and a lower voltage represents a lower pressure.
  • The audio signal is usually of two types
    * Analog audio * Digital audio
  • Analog audio are sampled and encoded into digital audio. Digital signal are represented as a series of binary numbers.
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  • In a digital system, an ADC converts physical sound to a digital signal using pulse code modulation/ any other encoding standard.
  • DAC will convert digital audio signal back to physical audio through an amplifier and speaker.
  • Components of a digital audio system include:
    1. Compression
    2. Storage
    3. Processing 4. Transmission