A microphone is a... - Answers Transducer, converting audio (sound waves) into an electric
signal
Ways of creating digital audio: - Answers Sampling and synthesis
Amplitude (a) - Answers related to intensity
Frequency (f) - Answers related to perceived pitch
Phase (theta) - Answers can depend on the relative location of the sound
Period is measured in... - Answers Hz or cycles/second
Digitizing sound involves... - Answers Taking samples (measurements) at a fixed rate (sampling
rate) and recording them
Too fast sampling rate means... - Answers large audio file
Too slow sampling rate... - Answers inaccurate audio file
Nyquist Shannon - Answers sample interval is less than/equal to half of the period
Bit depth - Answers the number of bits of information in each sample
higher bit depth means... - Answers more accurate sample
bit rate - Answers the number of bits that are conveyed or processed per unit of time
higher bit rate means... - Answers better quality, larger file
FLAC (Free Lossless Audio Codec) - Answers Lossless, compression ratio 62%, used for
archiving high quality audio, uses Hoffman and run-length encoding
MP3 (Moving Picture Experts Group Layer 3 Audio) - Answers Lossy, compression ratio 13%,
popular with most mobile devices, uses psychoacoustics and Huffman encoding and lower bit
rates
AAC (Advanced Audio Coding) - Answers Lossy, compression ratio of 14%, popular with Apple
devices/most smartphones, uses psychoacoustic, Huffman and lower bit rates
Colour is typically represented using... - Answers RGB colour model ( other color models are
CMYK, HSL and YUV)
Colours between red, green, blue can be represented by numbers between... - Answers 0 and
255
how many possible colours can be made with RGB colour model? - Answers (256)^3 possible
, colours
pixel (picture element) - Answers dots of colour in an image
resolution - Answers number of pixels in an image, size of an image measured in pixel.
sometimes resolution refers to pixel density , the number of pixels per unit of distance ( ex:
pixels per inch or ppi
vector graphics - Answers An image that is defined using mathematical equations representing
lines, curves, and polygons. Can be enlarged without loss of detail, or a change in file size image
is created using drawing applications or text editors. uses SVG
SVG - Answers scalable vector graphics: popular graphic format, SVG files are text-based and
can be compressed accordingly
raster graphics - Answers an image composed of a matrix of pixels, created/edited using
painting applications, suffers from pixelation, meaning that when enlarged the rectangular
shape of pixels becomes apparent
indexed colour - Answers Used for compressing images, only represents colors that are used
( like with keyword encoding but with colors)
GIF (Graphics Interchange Format) - Answers Lossless, indexed colors, coding related to
Huffman allows transparency and animation, compression ratio of 10%, low quality
PNG (Portable Network Graphics) - Answers lossless, indexed colors, allows transparency, run-
length encoding, a compression ratio of 7%, more modern, larger file
JPEG (Joint Photographic Experts Group) - Answers A lossy compression technique for color
images. Good for photos but not for images with text or sharp lines. A compression ratio of 1-
10%, depending on quality, reduces color resolution
Gate - Answers A device that performs a basic operation on electrical signals, accepting one or
more input signals and producing a single output signal
Circuits - Answers Gates combined to perform more complicated tasks
Boolean Expressions - Answers Evaluates to either true or false, two valued logic
Logic Diagram - Answers A graphical representation of a circuit; each type of gate has its own
symbol
Truth Table - Answers A table showing all possible input values and the associated output
values
Functional Notation - Answers Uses a function name followed by a list of arguments in place of
the operands used in Boolean expressions