Frequency Domain

In electronics, control systems engineering, and statistics, frequency domain is the domain for analysis of mathematical functions or signals with respect to frequency, rather than time. Put simply, a time-domain graph shows how a signal changes over time, whereas a frequency-domain graph shows how much of the signal lies within each given frequency band over a range of frequencies. A frequency-domain representation can also include information on the phase shift that must be applied to each sinusoid in order to be able to recombine the frequency components to recover the original time signal.

A given function or signal can be converted between the time and frequency domains with a pair of mathematical operators called a transform. An example is the Fourier transform, which decomposes a function into the sum of a (potentially infinite) number of sine wave frequency components. The 'spectrum' of frequency components is the frequency domain representation of the signal. The inverse Fourier transform converts the frequency domain function back to a time function. A spectrum analyzer is the tool commonly used to visualize real-world signals in the frequency domain.

Recent advances in the field of signal processing have also allowed to define representations or transforms that result in a joint time-frequency domain, with the instantaneous frequency being a key link between the time domain and the frequency domain.

Read more about Frequency Domain:  Magnitude and Phase, Different Frequency Domains, Discrete Frequency Domain, Partial Frequency-domain Example, History of Term

Famous quotes containing the words frequency and/or domain:

    The frequency of personal questions grows in direct proportion to your increasing girth. . . . No one would ask a man such a personally invasive question as “Is your wife having natural childbirth or is she planning to be knocked out?” But someone might ask that of you. No matter how much you wish for privacy, your pregnancy is a public event to which everyone feels invited.
    Jean Marzollo (20th century)

    The vice named surrealism is the immoderate and impassioned use of the stupefacient image or rather of the uncontrolled provocation of the image for its own sake and for the element of unpredictable perturbation and of metamorphosis which it introduces into the domain of representation; for each image on each occasion forces you to revise the entire Universe.
    Louis Aragon (1897–1982)