Signal processing

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Signal processing is the analysis, interpretation and manipulation of signals. Signals of interest include sound, images, biological signals such as ECG, radar signals, and many others. Processing of such signals includes storage and reconstruction, separation of information from noise (e.g., aircraft identification by radar), compression (e.g., image compression), and feature extraction (e.g., speech-to-text conversion).

[edit] Signal classification

Signals can be either analog or digital, and may come from various sources.

There are various sorts of signal processing, depending on the nature of the signal, as in the following examples.

For analog signals, signal processing may involve the amplification and filtering of audio signals for audio equipment or the modulation and demodulation of signals for telecommunications. For digital signals, signal processing may involve the compression, error checking and error detection of digital signals.

Analog signal processing—for signals that have not been digitized, as in classical radio, telephone, radar, and television systems
Digital signal processing—for signals that have been digitized. Processing is done by digital circuits such as ASICs, FPGAs, general-purpose microprocessors or computers, or specialized digital signal processor chips.
Statistical signal processing—analyzing and extracting information from signals based on their statistical properties
Audio signal processing—for electrical signals representing sound, such as music
Speech signal processing—for processing and interpreting spoken words
Image processing—in digital cameras, computers, and various imaging systems
Video signal processing—for interpreting moving pictures
Array processing—for processing signals from arrays of sensors