Data - All Flashcards
What is Sample Resolution?
The number of bits used to store each sample. The more bits used the better the accuracy of the file.
What is a Bitmap Image?
An image that has been stored as a series of values per pixel. The color of each individual pixel is stored in a file.
What is a Vector Graph?
An image file that is made up of lines and shapes that have certain properties, for example, a line may have the following properties: start point, end‐point, line color, line thickness, line style. The properties of each shape are stored in a file to make up the image.
What is a Pixel?
Short for picture element. It is the smallest component of a bit‐mapped image.
What is a Sample Interval?
The time period between taking samples/measurements.
The more frequently the sound is sampled, the better the quality of playback.
What is Colour Depth?
The number of bits used to represent the color of a single pixel in a bit mapped image. Higher color depth gives a broader range of distinct colors. For example, an image stored as a .gif file uses 8 bits per pixel so the image could use 256 different colors.
What is Metadata?
Data about data. In the case of image files metadata is the data the computer needs to interpret the image data in the file, for example: resolution, color depth and image dimensions.
What is meant by the resolution of the picture?
The number of pixels in an image expressed as the number of pixels across x the number of pixels down eg: 400 x 600.
Define Analogue
A continuously changing wave such as natural sound.
Define Digital
Data that is made up of separate values. How data is stored on a computer.
Define Sample Rate
The number of times per second that the sound wave is measured. The higher the rate the more accurately the sound wave is represented.
Define Sample interval
The time gap between measurements of the sound wave being taken.
Another way of expressing the sampling rate.
Define Sample resolution
The number of bits used to store the value of each sample. The higher the number of bits the more accurately the value is stored.
Define ADC
Analogue to Digital converter: take real‐world analogue data and converts it to a binary representation that can be stored on a computer.
Define Data
Facts and figures with no context or format to give them meaning.
Define Information
Processed data that has context and format so that it conveys meaning.
Convert the denary number 106 into an 8 bit binary number.
0 1 1 0 1 0 1 0
Convert the denary number 106 into Hexadecimal.
6 A
Explain how ASCII is used to represent text in a computer system.
Each character is given a numeric code, that is then stored in binary in the computer.
ASCII uses 1 byte to store each character.
The characters coded include letters, digits, punctuation marks and control characters such as tab and enter.
State what is meant by the character set of a computer.
The group of characters that can be represented on that computer
Unicode is also used to represent text in a computer system.
Explain the difference between the character sets of Unicode and ASCII.
ASCII uses 7 or 8 bits to represent each character so the character set can contain a maximum of 256 characters. Unicode uses 16 bits to encode each character so the
number of characters that can be represented is much higher (65,536 maximum with 16 bits).
What is ASCII?
American Standard Code for Information Interchange: a 7 bit character set used by PCs.
What is binary?
Base 2 number system, used by computers, uses the digits 1 & 0 only, also known as OFF or ON, and is the number system used by computers to store data and instructions.
What is Unicode/UTF-8?
A universal character set consisting of more than 1920 characters which characters from all languages.
Why is Unicode better than ASCII?
Because UTF-8 has characters from all languages and ASCII only has English characters.
What are Boolean Expression?
An expression that is either true or false eg; X=10
What are Truth Tables?
A table that shows all the possible combinations of inputs and their logical output value.
What are the Logical Operators?
AND, OR, NOT
What are Logic Diagrams?
A diagram of a circuit showing logic gates with inputs and the output these generate.
Convert 0101 0101 from base 2 to decimal
85
