Folders out, planners out… What is 75 in Binary? What is 1101 in Denary? What is 01011111 in Hexadecimal? (use whiteboards)

1. Be able to carry out binary conversion and arithmetic (ALL) 2. Be able understand how computers encode characters in ASCII (Grade 4 - MOST) 3. Be able to apply understanding of parity in error checking of data transmission (garde 5 – SOME)

Block Busters Challenge What is 5 X 2 in binary? What is 5 – 2 in binary? What is 7 + 2 in binary? What is overflow? What is signed integers? What is an unsigned integer? Describe sign and magnitude? Describe what a real number is? Describe two’s complement?

Negative numbers in binary Convert the following unsigned binary number 00000111 into a negative number using two’s complement.

Can you guess the phrase from this code? Breaking the code…. 67 111 109 112 117 116 101 114 32 83 99 105 101 110 99 101 32 105 115 32 67 111 111 108 Can you guess the phrase from this code?

Letters, Digits, Punctuation Marks… What is ASCII? PCs use a character set called American Standard Code for Information Interchange. A character set is the group of symbols that a computer can represent: Letters, Digits, Punctuation Marks…

Characters of other alphabets cannot be represented. What is ASCII? ASCII is a 7-bit character set. It includes at most 128 different characters. These characters are mainly from the Latin Alphabet. Characters of other alphabets cannot be represented.

ASCII Table

Can you guess the phrase from this code? Breaking the code…. 67 111 109 112 117 116 101 114 32 83 99 105 101 110 99 101 32 105 115 32 67 111 111 108 Can you guess the phrase from this code?

Challenge!! Create a coded phrase yourself in ASCII and see if your partner can decode it!! You have 10 minutes!!

Find out what is Unicode. HOMEWORK  Find out what is Unicode.

Data Transmission So far we have looked at how computers store information in the form of binary numbers. Inside the computer, we can use pulses of electricity to represent the 1s and 0s. These pulses can be sent along a wire, either around a computer or out to other devices.

Serial Transmission The most obvious way to send the pulses is one at a time. This is called serial transmission. wire 1 1 1 1

Parallel Transmission Pulses can also be sent in parallel. This is a quicker way to send data inside the computer. 1 1 1 1

How can we tell whether that has happened? Errors Sometimes interference can occur as data is transmitted. This is more likely to happen on long cables such as telephone and network cables. How can we tell whether that has happened? This is a quicker way to send data inside the computer. 1 1 1 1 1

Parity Parity is a system where you add an extra bit to the data so that you can check for errors. An extra check digit is added to the end of the binary number. All you need to do then is to count up the ones and see whether there is an odd or even number.

Parity - Example Assuming that we’re using odd parity, have errors occurred in these messages (the check digit is shown in blue)? 001010100 101010101 010101010 111111111 3 x 1 = odd OK 5 x 1 = odd OK 4 x 1 = even Error 9 x 1 = odd OK

Parity - Problems You cannot tell where the error has occurred. 001010100 101010101 010101010 111111111 You cannot tell where the error has occurred. An error is an even number of bits is undetected. 3 x 1 = odd OK 5 x 1 = odd OK 4 x 1 = even Error 9 x 1 = odd OK

Exercise Books Out! Draw a spider diagram to summarise your learning of ASCII. Draw a spider diagram to summarise your understanding of Data Transmission and Parity.

What are we learning now? Work it out and write it on a mini whiteboard.

1. Be able to understand how bitmap images are represented in binary (ALL) 2. Be able to know how analogue data is represented in binary (D - MOST) 3. Be able to apply understanding of binary to understand the limitations of sampling (C+ – SOME)

Sound Waves In exercise books, write out the title and date. Draw a sound wave and answer the following question: How are sound waves stored in a computer?

Binary – Sound Waves 101 The amplitude of a wave controls how loud the sound is. The frequency controls the pitch.

Sound Waves Sound waves are converted into binary values. The sound wave is sampled at specific time intervals and the amplitude measured.

Sound Waves This process is known as an Analog – Digital Converter (ADC)

Binary – Sampling Digital sound will sample the sound wave at certain points. After sampling we are left with a digital version of the sound.

Binary – Higher Sampling Rate By doubling the sample rate we can represent the original sound wave more closely. Increasing sample rate improves sound quality.

Sound Waves Task In exercise books, answer the following questions: What is the process of sampling a soundwave? What is higher sampling rate?

How would the computer store this image?

Pixels and Picture Resolution A picture on a computer is broken down in to small elements called pixels. A pixel is one particular colour. How big pixels are in an image (Resolution)

Pixels and Picture Resolution The colour of each pixel is stored as binary code.

Colour Depth If more bits are used to represent each pixel then more combinations of binary numbers and colours are possible. In the space invader example, only 1 bit represents a pixel, giving two possible colours (0 or 1).

Metadata What information does a computer need to understand about a picture? Data about the data file itself is called metadata.

Draw an image in binary  Images in Binary Draw an image in binary 

QUIZ TIME!!!