Text, Sound & Images (Cambridge (CIE) O Level Computer Science)
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Define character set.
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Define character set.
A character set is a defined list of characters that can be understood by a computer, where each character is given a unique binary code.
What is ASCII?
ASCII (American Standard Code for Information Interchange) is a character set that uses 7 bits, allowing it to represent a maximum of 128 characters.
True or False?
ASCII can represent characters from all major languages around the world.
False.
ASCII can only represent basic characters needed for English, limiting its use for other languages.
What is the definition of extended ASCII?
Extended ASCII is a character set that uses 8 bits, allowing it to represent a maximum of 256 characters.
Define UNICODE.
UNICODE is a character set that uses a minimum of 16 bits, allowing it to represent a minimum of 65,536 characters from all major languages around the world.
State the meaning of bit.
A bit is a single binary digit, representing either a 0 or 1.
True or False?
UNICODE uses more storage space than ASCII.
True.
UNICODE uses more storage space than ASCII because it uses more bits to represent characters.
What does character encoding mean?
Character encoding refers to the process of assigning a unique binary code to each character in a character set.
True or False.
A drawback of ASCII is that it cannot represent special characters such as emoji's?
True.
A drawback of ASCII is that it cannot represent special characters such as emoji's (not enough bits)
What is the equation in terms of X for the maximum number of characters in a character set using X bits?
Maximum number of characters =
(to the power of the number of bits)Define sampling.
Sampling is the process of measuring and capturing values of an analogue signal at regular intervals.
What is an analogue signal?
An analogue signal is a continuous signal that can take on any value within a range, such as a sound wave.
True or False?
Sound must be converted from analogue to digital form for a computer to process it.
True.
Sound must be converted from analogue to digital form for a computer to process it.
What does Analogue to Digital conversion (A2D) mean?
Analogue to Digital conversion (A2D) is the process of converting an analogue signal, such as sound, into a digital form that a computer can understand.
Define sample rate.
Sample rate is the amount of samples taken per second of an analogue signal, measured in Hertz (Hz).
State the meaning of sample resolution.
Sample resolution is the number of bits stored per sample of the sound.
True or False?
Higher sample rate and bit depth result in better sound quality but larger file sizes.
True.
Higher sample rate and bit depth result in better sound quality but larger file sizes.
What does amplitude mean in the context of sound waves?
Amplitude refers to the height of a sound wave.
True or False?
The sample rate of a typical audio CD is 44.1 kHz (44,100 samples per second).
True.
The sample rate of a typical audio CD is 44.1 kHz (44,100 samples per second).
What is the definition of digital?
Digital refers to data represented as a series of discrete values, typically 0s and 1s in binary.
Define duration.
Duration is the length of time that something lasts, in the context of sound, it refers to the length of the recorded audio.
Define bitmap.
A bitmap is an image made up of squares called pixels, where each pixel is stored as a binary code.
What is a pixel?
A pixel is the smallest element of a bitmap image.
True or False?
A vector image is created from mathematical equations and points.
True.
A vector image is created from mathematical equations and points.
Define resolution.
Resolution is the total amount of pixels that make up a bitmap image, calculated by multiplying the height and width of the image (in pixels).
What does colour depth mean?
Colour depth is the number of bits stored per pixel in a bitmap image.
State the equation in terms of X for the maximum number of colours in an image with colour depth X.
Maximum number of colours =
(2 to the power colour depth)Example: Colour depth = 8, 28 = 256 colours
True or False?
Higher resolution and colour depth result in larger file sizes.
True.
Higher resolution and colour depth result in larger file sizes.
What is the definition of metadata?
Metadata is data about data, or additional information stored with an image but not required to display the image.
What is the meaning of True Colour?
True Colour refers to a colour depth of 24 bits, allowing for 16,777,216 colours.
Define pixel depth.
Pixel depth is another term for colour depth, referring to the number of bits used to represent the colour of each pixel.