Digital audio

Digital audio represents sound as discrete numerical measurements or encoded symbolic information. It can be stored, processed, and transmitted as data.

Sampling (signal processing): Sampling converts a continuous-time signal into a sequence of values measured at discrete time intervals. Its sampling rate sets how frequently digital audio records the changing waveform.
Analog signal: An analog signal varies continuously in time or amplitude and can represent changing physical quantities. Digital audio samples an analog sound signal before representing it numerically.
WAV: WAV is a container format commonly used to store uncompressed PCM audio. It commonly carries high-quality digital recordings without lossy compression.
Lossy compression: Lossy compression reduces data size by permanently discarding information judged less necessary. It explains the irreversible information loss in formats such as MP3.
Quantization (signal processing): Quantization maps a range of continuous values to a finite set of discrete levels. It determines the amplitude precision of sampled audio and contributes quantization noise.
Frequency: Frequency is the number of repetitions of a periodic event per unit of time. A sound's frequency determines its pitch and its position within an audio signal's spectrum.
MP3: MP3 is a lossy audio coding format that reduces file size using perceptual compression. It illustrates how digital audio can trade discarded detail for smaller files.
Lossless compression: Lossless compression reduces data size while allowing exact recovery of the original data. It offers smaller files without altering the decoded audio samples.
Pulse-code modulation: Pulse-code modulation represents sampled signal amplitudes as binary numbers, commonly using fixed-length words. PCM is the standard uncompressed representation used by formats such as audio CDs.
Amplitude: Amplitude is the magnitude of variation in a wave or other changing quantity. Sample values encode waveform amplitude, which relates to sound pressure and loudness.

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