Representing sound Flashcards
How do bit patterns represent sound?
Analogue sound is picked up with a microphone, the signals are processed using an ADC. Samples are taken at regular time intervals, each measurement is assigned a bit pattern.
ADC
Analogue to Digital Converter
DAC
Digital to Analogue Converter
How does sound processing work?
Sound waves vibrate a microphone, the analogue sound waves are translated into digital sound data using an ADC, this data is then stored.
What does an ADC do?
Converts analogue sound waves to digital sound data
What does a DAC do?
Converts digital sound data to analogue sound waves
What is sample resolution?
The number of bits used to represent each sample (bits per sample)
What is sampling rate?
Number of samples taken per second measured in hertz (samples per second)
What is the Nyquist Theorem?
In order to have an accurate representation of a signal, the sampling rate has to be at least twice the highest frequency present in the signal. (Sampling rate >= 2Fmax)
How do you calculate the storage size of sound?
(in bits) sampling rate x sample resolution x seconds
What are event messages in MIDI?
Event messages are pieces of data that specify the information required to produce sound.
What are the advantages of using MIDI?
A MIDI file uses less storage space than a sampled recording of similar quality. Music can also be easily manipulated for example, changing the pitch of a single note.
