OCR J277 Sound Data Representation Visualiser

GCSE controls Simple + clear

Sample rate (Hz) = samples per second

Bit depth (bits) = bits per sample

Display length (ms) (time window shown)

Scroll along clip (start time, seconds)

Channels (for file size)

Duration (s) (for file size)

KB base

Wave source (for the picture + sound)

Fun extra

Show bit-depth clearly

Sampling interval

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Quantisation levels

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Bit rate

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File size

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Key GCSE sentence (say it like OCR):
Sampling is when the amplitude of the sound wave is measured at regular intervals and stored as binary.
Sample rate = samples per second (Hz). Bit depth = bits per sample.

File size method:

size(bytes) = (sampleRate × bitDepth × channels × duration) ÷ 8

Visual explanation Blue (original) • Green (samples) • Red (quantised)

Waveform view (time window)

Change sample rate (dot spacing) and bit depth (step choices)

Original (analogue idea) Samples (measured amplitudes) Quantised steps (bit depth) Quantisation error (magnified)

Quantisation error (magnified so bit depth is obvious)

Lower bit depth → bigger error “wiggle”

Teacher move: set bit depth = 3 or 4 first, then move to 8 and 16. Use the yellow error trace to make the improvement visible.