Represent text sound and graphics Flashcards
What does ASCII stand for?
American Standard Code for Information Interchange
How many bits does ASCII use?
7
How is it structured?
A-65 s mall a-97
What is a character set?
A list of characters recognised by software and hardware
What is the 8th bit for
Error checking(even number of 0’s and 1’s)
Give 1 benefit of the extended ASCII code
additional £ sign
What was the task of UNICODE?
To create a character set used globally
What is ord used for?
To find out a character’s ASCII code
e.g. ord(“A”)is 65
What is difference between amplitude and frequency?
Amplitude is how loud the noise is but frequency is how long it is
What does the microphone do?
Converts sound to electrical energy
What is the sound-card responsible for?
Converting electrical signal from microphone to binary signal
What is sample rate?
Samples sound wave at regular intervals
What are the steps?
1.Sound waves are analogue so changes continuously
2.To record sound it is first recorded with a microphone
which converts sound energy to electrical energy
3. Analogue electrical signal sampled at regular intervals-sample rate by the sound card
4. At each sampling the value of electrical signal is rounded up or down.And binary value point is recorded.
How do you work out file size
File size (bits)=Sample rate(Hz)*Sample resolution *Length(sec)
What are pixels?
Small dots that make up a bitmap image
How do you work out file size in images?
File size(bits)=image resolutioncolour depth=width* height*colour depth
