Signal processing transforms or analyzes signals to extract information, change a representation, or improve a measurement. Examples include smoothing a sensor record, selecting a band of frequencies, and decomposing a recording through Fourier analysis. A signal is a mathematical representation of a physical record; deciding which variation is meaningful and which is noise is part of the problem.
A linear filter offers a simple entry point. Its output is assembled from weighted copies of its input. A moving average can reduce rapid variation, but it also changes timing and can erase useful detail. The worked example below makes that tradeoff explicit rather than treating a smoother plot as automatic improvement.
Two complementary views make the subject appealing. An impulse response describes the effect of a localized input; a frequency response describes the effect of a sustained oscillation. For a linear time-invariant system, both describe the same operation, connected by convolution and Fourier analysis. [ref]
https://ocw.mit.edu/courses/res-6-007-signals-and-systems-spring-2011/0400ba59406d52d94c079d99928156ee_MITRES_6_007S11_lec04.pdf. Alan Oppenheim, MIT Signals and Systems, lecture 4: impulses, complex exponentials and convolution
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Signal processing is a field of engineering and applied mathematics that focuses on the analysis, manipulation, and interpretation of signals. A signal is typically a function that conveys information about a phenomenon, which can be in various forms such as time-varying voltage levels, sound waves, images, or even data streams. Signal processing techniques are used to enhance, compress, transmit, or extract information from these signals.
