Computing
Computer Science LearnITWithMrC ⛯ Year 7 Year 8 Year 9 GCSE
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Lesson Video

50

Lesson Tasks

  • Watch the Lesson video
    Make notes on your notes sheet.
  • Read the lesson notes
    Make notes on your notes sheet.
  • Complete the learning activities
    Make any notes on your notes sheet.
  • Check the Learning outcomes
    Update your learning objectives

What do I need to Learn?

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I need to learn how to understand that sound is analogue and that it must be converted to a digital form for storage and processing in a computer.
I need to learn how to understand that analogue signals are sampled to create the digital version of sound.
I need to learn how to describe the digital representation of sound in terms of sampling rate.
I need to learn how to describe the digital representation of sound in terms of sample resolution.
I need to learn how to calculate sound file sizes based on the sampling rate and the sample resolution.

Key Terms

analogue signal analogue-to-digital converter (ADC) digital-to-analogue converter (DAC) sampling rate sample resolution file size Hertz(Hz)

Task 1 - Getting organised Click to see more


Task: Learning Journal

Open your Learning Journal by clicking on the image below

Good notes will help you organise and process data and information


Task 2 - Sample Resolution Click to see more

Representing Sound - Sample Resolution

Sound is stored according to sample rates. The higher the sample rate, the better the quality, but the larger the file size.

The MP3 file format was designed to encode a raw audio file as a sequence of zeros and ones.

Click on the image below to find out about Sampling sound


Example:Sampling Sound

Run the python sampling interval code below see what you can notice about the connection between the sampling rate and the analogue sound wave




Task:

Open your student workbook at page 47 Read through the notes then complete the following tasks in your book.
  1. Task 26

  • When you are finished screenshot your answer into your Learning Journal

  • Task 3 - File Size Click to see more

    Bit rate

    Task:Sound Sampling - Revision

    Click on the image below to try the sampling sound revision task



    Task:

    Open your student workbook at page 51 Read through the notes then complete the following tasks in your book.
    1. Task 27
    2. Task 28
    3. Task 29

  • When you are finished screenshot your answer into your Learning Journal

  • Task 4 - Exam style Questions Click to see more

    Task:Exam Questions

    Try and answer the exam questions below using your notes to help you

    Questions

    Describe the differences between analogue and digital recordings. - [4 Marks]

    An eight second file has been recorded with a sample rate of 10Hz and a sample resolution of 6 bits. How large will that file be in bytes? Show your working. - [3 Marks]

    A microphone is left on for 20 hours recording MP3 audio files. If an MP3 uses 1MB in one minute, How large will that file be in Gigabytes? Show your working. - [4 Marks]





    Task 5 - Lesson Review/Homework Click to see more


    Complete any unfinished tasks

    Summing it all up

    Lets look at the learning outcomes and decide which one best describes our current level of understanding :

    Tick the one you feel is closest to your level

    Learning Outcomes

    • I have a basic understanding of how with a little help from my teacher
    • I can show my teacher that without their help.
    • independently and I can also explain it to others and can complete any extension tasks I am given.

    🠜 Now update your learning objectivesClick on the Assessment image