Computer Science - 4CP0 PearsonEdexcel

Data Representation

Bayani Gaba-gaba

A photograph, a song and a paragraph of text look nothing alike, yet a computer stores all three the same way: as binary digits. The difference is entirely in how those digits are agreed to be interpreted, letter by letter for text, pixel by pixel for an image, sample by sample for sound.

In this lesson you will learn how characters are encoded using ASCII and Unicode, how a bitmap image's resolution and colour depth determine its uncompressed file size, how an analogue sound wave is converted into binary using sampling, and why the number of bits available always limits how faithful any of these digital representations can be.

Manufura

  1. Understand how computers encode characters using ASCII and Unicode
  2. Understand how bitmap images are represented in binary (pixels, resolution, colour depth)
  3. Understand how sound, an analogue signal, is represented in binary
  4. Understand the limitations of binary representation of data (sampling frequency, resolution) when constructed by the number of available bits

Takardar Darasi

A computer has no built-in idea of what a letter is. To store text, every character a keyboard can produce is given its own unique binary number, called a character code. ASCII (American Standard Code for Information Interchange) does this using 7 bits, giving 128 possible codes, enough for the upper- and lower-case English alphabet, digits, punctuation and basic control characters. An 8-bit version, extended ASCII, adds a further 128 codes for accented letters and symbols.

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Zazzage manhajar Green Bridge CBT a wayar ka ko kwamfyuta ka don samun cikakkiyar bayanan darasi, tambayoyin aiki, da ƙari.

Cikakkiyar bayanan darasi tare da zane-zane
Mataimakiyar koyo da AI
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Akwai a Android, Windows, macOS, da Linux

Nazarin Darasi

Barka da kammala darasi akan Data Representation. Yanzu da kuka bincika mahimman raayoyi da raayoyi, lokaci yayi da zaku gwada ilimin ku. Wannan sashe yana ba da ayyuka iri-iri Tambayoyin da aka tsara don ƙarfafa fahimtar ku da kuma taimaka muku auna fahimtar ku game da kayan.

Za ka gamu da haɗe-haɗen nau'ikan tambayoyi, ciki har da tambayoyin zaɓi da yawa, tambayoyin gajeren amsa, da tambayoyin rubutu. Kowace tambaya an ƙirƙira ta da kyau don auna fannoni daban-daban na iliminka da ƙwarewar tunani mai zurfi.

Yi wannan ɓangaren na kimantawa a matsayin wata dama don ƙarfafa fahimtarka kan batun kuma don gano duk wani yanki da kake buƙatar ƙarin karatu. Kada ka yanke ƙauna da duk wani ƙalubale da ka fuskanta; maimakon haka, ka kallesu a matsayin damar haɓaka da ingantawa.

  1. The upper-case letter 'A' has the ASCII code 65. What is the ASCII code of the lower-case letter 'a'? A) 33 B) 66 C) 97 D) 129 Answer: C
  2. An image is 100 pixels wide, 50 pixels tall, and uses a colour depth of 8 bits. What is its uncompressed file size in bits? A) 4 000 B) 8 000 C) 40 000 D) 400 000 Answer: C
  3. Which setting controls how many amplitude levels a single digital audio sample can be stored as? A) Sample rate B) Bit depth C) Number of channels D) File format Answer: B
  4. A recording is made with too low a sample rate. What is the most likely effect on the digital recording? A) The file becomes larger than expected B) Rapid changes in the original sound are missed C) The recording gains extra colour depth D) The recording becomes louder Answer: B
  5. What is the main reason Unicode was developed alongside ASCII? A) To make text files smaller B) To represent far more characters than ASCII can, covering the world's writing systems and symbols C) To replace binary with a new number system D) To increase a computer's sample rate Answer: B

Akwai a cikin manhajar Green Bridge

Zazzage manhajar Green Bridge CBT a wayar ka ko kwamfyuta ka don samun cikakkiyar bayanan darasi, tambayoyin aiki, da ƙari.

Cikakkiyar bayanan darasi tare da zane-zane
Mataimakiyar koyo da AI
Yi karatu ba tare da intanet ba, a kowane lokaci, a ko'ina
Akwai a Android, Windows, macOS, da Linux

Akwai a cikin manhajar Green Bridge

Zazzage manhajar Green Bridge CBT a wayar ka ko kwamfyuta ka don samun cikakkiyar bayanan darasi, tambayoyin aiki, da ƙari.

Cikakkiyar bayanan darasi tare da zane-zane
Mataimakiyar koyo da AI
Yi karatu ba tare da intanet ba, a kowane lokaci, a ko'ina
Akwai a Android, Windows, macOS, da Linux

Yi Aikin Tambayoyin Gwaji

Kana son yin aikin tambayoyin gwaji kan Data Representation? Sauke manhajar Green Bridge CBT don samun tambayoyin gwaji da cikakkun jarrabawa akan wannan batu.

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