Data Representation Flashcards
(31 cards)
Which numbers are stored in one bit?
0 and 1
How many bits are there in a nibble and a byte?
Nibble = 4 bits Byte = 8 bits
Why does computers use binary?
-Computers use circuits which can be on or off, represented by 1 and 0
-Computers also operate using logic gates which only have two states, true or false
Explain one limitation of ASCII character set
-ASCII only uses 7 bits so it can only represent 128 characters
-This is not enough to represent characters in other alphabets
Name a character set designed to overcome this limitation
-Unicode
Why are colour codes given in hexadecimal rather than binary?
-Easier to read and remember compared to binary
-Less chance of making an error if inputting in hexadecimal
Define the meaning of resolution
The number of pixels in the image
How does the colour depth affect the file size?
Additional colours would increase the bit depth causing the image size to double.
Explain the effect of increasing the sample resolution on the quality of a sound file?
-Increasing the sample resolution will mean that the sound is sampled more accurately
-More data will be required per sample which will improve the quality of the sound
Explain the effect of increasing the sample rate on the size of the sound file
-Will increase the number of samples taken each second
-Will increase the file size
Define the meaning of the term lossy compression
Some data will be permanently lost in the compression process
Define lossless compression
Loseless compression will not lose any of the original data during the compression
Examples of lossy compression
-JPG
-GIF
-MP3
Examples of loseless compression
-PNG
-TIFF
Explain data compression
-Reducing the amount of bits required to represent data
-Used to reduce the amount of storage space to store the amount of data that needs to be transmitted
Explain Run length encoding
-An algorithm to compress data that uses frequency pairs to reduce the amount of data stored
What is a bitmap graphic made up from?
Individual pixels
What is colour depth?
It determines the number of available colours for an image
What happens to the file size when the resolution is greater?
The file size will become greater
Types of bitmap image file formats
-BMP
-TIFF
-PNG
-JPG
-GIF
Type of vector image file format
-SVG
The sample unit is measured in what unit?
Hertz
What is resolution
The number of bits available to store each sample
Formula for calculating the size of an uncompressed file
Sample rate x resolution x duration
