Zusammenfassung der Ressource
Data
Representation
- Binary
conversions
- Adding
binary
- 1011
+1111
11010
- If it's a double
1 it's makes 1
and you
carry another
1
- If it's a 1
and a 0 you
put a 0 and
carry the 1
- Hexadecimal and Deanery
- 0-9 are numbers
10-15 are A-F
- 10110111
- First split it
down the
middle
- 1011|0111
- Then it
becomes a
nibble each
side
- Add up
each nibble
- 11|7
- Then see if
any are to
be
converted
into letters
- 11=B
- You
answer is
B7
- ASCII
code
- A=65
a=97
- ASCII code does
represent
emojis Unicode
does
- Bits/nibbles
- Bit is a
single
binary
integer
- 4 bits
make a
nibble
- 8 bits make
a bite
- Binary
images
- Pixels
- Pixels are
the picture
element so
what the
screen is
made up of
- You can find
out how many
pixels there
are but finding
the area of the
screen
- Black+white
images/
colour
images
- If it's a black and
white image
1=black and
0=white
- For colour images
black would be the
highest integer
and white would
be the lowest
- A bit depth is how
many bits are
used to represent
the colours or the
colour depth
- 2 to the power
of colours used
x W x H = bit
depth
- Meta data
- The resolution of
the picture and
colour depth
- Lossy/lossless
compression
- Lossy
compression
- Reducing
the file
size
- But you
can't get it
back once
it's deleted
- JPEG uses
lossy
compression
- Lossless
compression
- Reducing
the file
size
- You can
get the
data back
if you want
- PNG uses
lossless
compression
- Lossless and lossy
compression is
when the photo
becomes
compressed and the
quality of the photo
goes down
- Sound
representation
- The wave
- Amplitude
is how
loud the
sound is
- Wavelength is the
distance between
a on one wave
and the same
point on another
wave
- It's easier to
measure from
the crest of one
wave and the
same point on
the next wave
- Frequency
and pitch
- Frequency is the
pitch of a sound the
closer the wave the
higher the pitch. The
longer the wave the
lower the pitch
- The frequency is
measured in Hertz
(Hz), Kilohertz
(KHz) and
Gigahertz (GHz)
- A frequency of 1 Hz
means one wave per
cycle per second. A
frequency of 10 Hz
means 10 wave cycles
per second where the
cycles are short and
closer together
- Sound on a
computer
- Sound created
on a computer
exist as digital
information
encoded as
audio files
- Stages of
making
digital
sound
- 4. The computer
then displays the
digitalised sound
for manipulation
- 3. An analogue to
digital converter
digitalises the
electrical voltage
to bytes of
information
- 2. Microphone
changes the air
pressure into
electrical
voltage
- 1.
Microphone
measures
changes in
air pressure