معالجة الإشارة

Signal processing is an electrical engineering subfield that focuses on analysing, modifying, and synthesizing signals such as sound, images, and scientific measurements.^[1] Signal processing techniques can be used to improve transmission, storage efficiency and subjective quality and to also emphasize or detect components of interest in a measured signal.^[2]

Signal transmission using electronic signal processing. Transducers convert signals from other physical waveforms to electric current or voltage waveforms, which then are processed, transmitted as electromagnetic waves, received and converted by another transducer to final form.

The signal on the left looks like noise, but the signal processing technique known as the Fourier transform (right) shows that it contains five well-defined frequency components.

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التاريخ

According to Alan V. Oppenheim and Ronald W. Schafer, the principles of signal processing can be found in the classical numerical analysis techniques of the 17th century. They further state that the digital refinement of these techniques can be found in the digital control systems of the 1940s and 1950s.^[3]

In 1948, Claude Shannon wrote the influential paper "A Mathematical Theory of Communication" which was published in the Bell System Technical Journal.^[4] The paper laid the groundwork for later development of information communication systems and the processing of signals for transmission.^[5]

Signal processing matured and flourished in the 1960s and 1970s, and digital signal processing became widely used with specialized digital signal processor chips in the 1980s.^[5]

الأصناف

Analog

معالجة الإشارة هو علم يعتني بإستخراج المعلومات المخزنة في هذه الإشارة. فمثلا:

إشارة ECG قد يستخرج منها معلومات مهمة عن القلب.
إشارة EEG قد يستخرج منها معلومات مهمة عن نشاطات الدماغ.

تقنيات معالجة الإشارة

انظر أيضاً

الهامش

^ Sengupta, Nandini; Sahidullah, Md; Saha, Goutam (August 2016). "Lung sound classification using cepstral-based statistical features". Computers in Biology and Medicine. 75 (1): 118–129. doi:10.1016/j.compbiomed.2016.05.013. PMID 27286184.
^ Alan V. Oppenheim and Ronald W. Schafer (1989). Discrete-Time Signal Processing. Prentice Hall. p. 1. ISBN 0-13-216771-9.
^ Oppenheim, Alan V.; Schafer, Ronald W. (1975). Digital Signal Processing. Prentice Hall. p. 5. ISBN 0-13-214635-5.
^ "A Mathematical Theory of Communication – CHM Revolution". Computer History. Retrieved 2019-05-13.
^ ^أ ^ب Fifty Years of Signal Processing: The IEEE Signal Processing Society and its Technologies, 1948–1998. The IEEE Signal Processing Society. 1998.

وصلات خارجية

Signal Processing for Communications – free online textbook by Paolo Prandoni and Martin Vetterli (2008)
Scientists and Engineers Guide to Digital Signal Processing – free online textbook by Stephen Smith

[1] Sengupta, Nandini; Sahidullah, Md; Saha, Goutam (August 2016). "Lung sound classification using cepstral-based statistical features". Computers in Biology and Medicine. 75 (1): 118–129. doi:10.1016/j.compbiomed.2016.05.013. PMID 27286184.

[2] Alan V. Oppenheim and Ronald W. Schafer (1989). Discrete-Time Signal Processing. Prentice Hall. p. 1. ISBN 0-13-216771-9.

[3] Oppenheim, Alan V.; Schafer, Ronald W. (1975). Digital Signal Processing. Prentice Hall. p. 5. ISBN 0-13-214635-5.

[4] "A Mathematical Theory of Communication – CHM Revolution". Computer History. Retrieved 2019-05-13.

[fifty-5] أ ^ب Fifty Years of Signal Processing: The IEEE Signal Processing Society and its Technologies, 1948–1998. The IEEE Signal Processing Society. 1998.

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