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Computer Science IGCSEPDF 9
142 pagesrevision 46930
PDF 9
Page image rendered from the stored file at 110 dpi; it sharpens as you zoom. Outlines are placed from each region’s stored position on the page (612 × 792 pt).
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Source of this text: embedded text layer. The better of the embedded text and OCR is kept.
Bit Depth / Sample Resolution – bits per sample.
Amplitude – wave height (volume).
Sample Rate – samples per second.
Resolution – pixels in image.
Colour Depth – bits per pixel.
RLE – lossless compression storing repeated values.
Lossy Compression – removes data, irreversible.
Lossless Compression – keeps all data, reversible.
ASCII – 7-bit character set.
Unicode – universal multi-language encoding.
UTF-8 – variable-length (1–4 bytes).
-Show working for conversions.
-Always write correct units (bits, bytes, KB, MB).
-Know ASCII vs Unicode, Lossy vs Lossless.
-Practise file size calculations for text, images, and sound.
-Mention amplitude and sample resolution when describing sound.
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