Computer Science 1033A/B Lecture Notes - Lecture 12: Bit Rate, Sample Size Determination, Hertz

• School: Western University
• Department: Computer Science
• Course: Computer Science 1033A/B
• Professor: Laura Reid

Document Summary

Sound pressure waves of air: series of recurring waves called waveform, height/amplitude of wave indicates volume (higher = louder, closeness of waves indicated frequency/pitch (closer = higher, sound is represented in digital form (1s and 0s) Computers have sound card which converts sound wave from a mic (a d) Laptops don"t have bc sound circuitry is incorporated into system board. Sound card has: adc: analog to digital converer (for recording, dac: digital to analog converter (for playing audio, operating system (ex. windows, os x) talks to sound card to handle actual recording and playback. Sample rate: number of samples we take per second of audio/number or times per second waveform is measured, number of samples/second is hertz (hz, 1000 samples/second is kilohertz (khz, typical sample rates. Cd 44. 1 khz: nyquist limit: must take at least 2 samples for every wave cycle. Higher pitch more samples: lots of samples: better quality, bigger file size.