A signal is a detectable quantity representing such physical properties as electrical potential, pressure, temperature or concentration. Signals are either analog or digital. If a quantity varies continuously, it is an analog signal, whereas digital signals are defined by a series of discrete measurements. Digital signals are relatively easy to reproduce and manipulate, and their proliferation among the various scientific fields has been accompanied by the rapid development of digital signal processing (DSP) techniques. Generally speaking, modern computing relies on the processing of digital signals, and so for our purposes, use of the term signal will refer to digital signals.
Signal processing refers to various manipulations or transformations performed on a measured signal. For example, we can use Fourier transforms to analyze the frequency spectrum of a signal, or we might use smoothing or other techniques to remove "noise" from a contaminated signal. Origin provides a number of tools suited to general signal processing tasks. These include tools for filtering or for transforming, including Fourier transforms and Wavelet transforms. Also included are tools for convolution, deconvolution, correlations, coherence, smoothing, and short-term Fourier transforms. Please note that some tools are only available in OriginPro.