Binary,Hex,Logic gates, images, sound, compression Flashcards
NEED FOR Y10 EXAM
how many values can a single bit represent?
2 - 1 and 0
how many bits are in a nibble?
4 bits
how many bits are in a byte?
8 bits
what values are used in a binary converting table of 8 bits?
1,2,4,8,16,32,64 and 128
How many values can 8 bits represent?
256
what would the sum of the binary numbers 00110011 and 01000010 equal?
01110101
What would a one place right shift do to a binary number?
Divide the number by 2 (half)
What would a one place left shift do to a binary number?
Multiply the number by 2 (Double)
what does F stand for in denary numbers?
15
what does A stand for in denary numbers?
10
What can Hexadecimal also be called and why?
Base-16, because it uses sixteen different didgets
What is ASCII?
The most commonly used character set in the English speaking world. Each ASCII character is given a 7-bit binary code - it can represent 128 different characters.
What is Extended ASCII?
a character set which gives each character and 8-bit binary code, allowing for 256 characters to be represented, useful for many European languages like french and German that include accents on some vowels. The first 128 characters are the same order as the ASCII characters.
what is Unicode?
a 16 - 32 bit character set, it tries to cover every written language, and covers all major languages, even those that use a completely different alphabet like Greek or Russian.
What is the relationship between the number of bits and the colour depth of an image?
The more bits = the deeper colour depth
how many colours can a 1-bit, 4-bit and 24-bit image show?
2^1 = 2 colours 2^4 = 16 colours 2^24 = 16,777,216 colours
What is colour depth?
The number of bits used for each pixel
What is MetaData?(images)
the information stored in an image file which helps the computer recreate the image on screen from the binary data in each pixel, it is needed to display images on a screen
What is a bitmap image?
the type of image you use most often, and made up of lots of tiny dots called pixels.
What is Resolution?
Resolution is the density of pixels in an image, like how many pixels are within a certain area. The higher he resolution the better the quality of the image
What is resolution measured in?
measured in dots per inch (DPI)
How is sound recorded?
By a microphone as an analogue signal
What is an Analogue Signal?
Pieces of continually changing data (sound)
What do Analogue signals need to be converted to? (sound)
Digital data so computers can store and read sound files, done by analogue to signal converters.
What is the process of converting analogue to digital called?
Sampling
What is a sampling interval?
The gaps between each end of the points where the analogue recording is sampled.
If an audio is sampled every 5 milliseconds, what would the sampling interval be?
5 ms
What is sample frequency?
Sample frequency (sample rate) is how many samples you take in a second, usually measured in Kilohertz (KHz)
what links bit rate, sampling frequency and sample size?
bit rate = sampling frequency x sample size
what happens the higher the sampling frequency?
the higher the sampling frequency, the better the quality of the original recording
what is Data Compression?
Data Compression is when we make file sizes smaller while trying to make the compressed file as true to the original as possible.
what is Lossy compression?
Lossy compression works by permanently removing data from the file, this limits the number of bits the file needs so it reduces its file size
What is Lossless Compression?
Lossless Compression makes the file size smaller by temporarily removing data to store the file and then restoring it to its original state when it’s opened
What are the Pros of Lossy Compression?
- Greatly reduces file size, so more files can be stored
- Lossy files take up less bandwidth so can be streamed and downloaded quicker
- Lots of software can read it
What are the Cons of Lossy Compression?
- Permanently removes data, so files cannot be turned back into their original state
- Cant be used on text or software files because they need to retain all the original information
- Worse quality than original, however not usually visually noticeable
What are the Pros of Lossless Compression?
- Data is removed temporarily, so there is no reduction in the quality of a file
- Lossless files can be decompresses, turned back into the original
- Can be used on text and software files
What are the Cons of Lossless Compression?
-Only a slight reduction in file size, so lossless files still take up quite a bit of storage on a device
Lossy compression file types
MP3 (Audio)
AAC(Audio)
JPEG(Image)
Lossless compression file types
FLAC(Audio)
TIFF(Image)
PNG(Image)
What is a NOT gate?
A NOT gate takes a single input, and gives a single output. The output is always the opposite value to the input.
What is a AND gate?
An AND gate takes two inputs and gives one output.
What is a OR gate?
An OR gate takes in two inputs and gives one output.
What is the output of a NOT gate?
Always the opposite value to the input
if the input is 1, the output is 0
If the input is 0, the output is 1
what are the outputs of a AND gate?
if both inputs are 1, the output is 1
if one input is 1, the output is 0
if both inputs are 0, the output is 0
What are the outputs for an OR gate
if both inputs are 1, the output is 1
If one input is 1, the output is 1
if both inputs are 0, the output is 0
What are the shapes of NOT, AND and OR gates?
Triangle
square-semicircle
Blown out triangle
