Energy (signal processing)

In signal processing, the energy of a continuous-time signal x(t) is defined as

the energy of a discrete-time signal x(t) is defined as

Relationship to energy in physics

Energy in this context is not, strictly speaking, the same as the conventional notion of energy in physics and the other sciences. The two concepts are, however, closely related, and it is possible to convert from one to the other:

For example, if x(t) represents the potential (in volts) of an electrical signal propagating across a transmission line, then Z would represent the characteristic impedance (in ohms) of the transmission line. The units of measure for the signal energy would appear as volt²·seconds, which is not dimensionally correct for energy in the sense of the physical sciences. After dividing by Z, however, the dimensions of E would become volt²·seconds per ohm, which is equivalent to joules, the SI unit for energy as defined in the physical sciences.

Spectral energy density

Seven Year Itch (Collective Soul album)

On September 18, 2001, Collective Soul released their greatest hits compilation Seven Year Itch: Greatest Hits, 1994-2001 (stylized as 7even Year Itch). The compilation includes songs recorded from 1994 to 2001 and included two new tracks; "Next Homecoming" and "Energy". Seven Year Itch received decent reviews and was relatively successful It sold 225,000 copies in the first year after its release and reached number fifty on the Billboard 200; in Canada, it reached number nine on its albums chart and went platinum. All the songs in Seven Year Itch had charted in the US on the Billboard Hot 100, Mainstream Rock Tracks, or the Modern Rock Tracks chart, except for "Energy", which debuted in this compilation.

The compilation has sold over 500,000 copies. It saw a resurgence in sales after Collective Soul began putting out albums on their own independent label, El Music Group, beginning in 2004.

Seven Year Itch was the last album Collective Soul released through Atlantic Records and their last album to feature guitarist Ross Childress, who had been with the band since its 1993/1994 debut.

Energy (Drake song)

"Energy" is the second single by Canadian rapper Drake from his fourth commercial release If You're Reading This It's Too Late.

Composition

"Energy" contains samples from Eazy-Duz-It performed by Eazy-E and Ridin Spiners performed by Three 6 Mafia. Energy was produced by Boi-1da and OB O'Brien. According to WhoSampled the song samples the score of an episode of The O.C..

Critical reception

"Energy" received acclaim from music critics with many calling it the best song of the album. Ryan Dombal of Pitchfork gave the song a positive review and named it "Best New Track", stating "The song isn't aimed to any rappers or pop stars, not Kendrick Lamar, Big Sean or Tyga, but the song lines are dangerous."

Music video

Release

The video of "Energy" was released on Apple Music and users with iTunes and registered Apple Music account can watch this video.

Synopsis

Quality (philosophy)

A quality (from Latin qualitas) is an attribute or a property. In contemporary philosophy the idea of qualities, and especially how to distinguish certain kinds of qualities from one another, remains controversial.

Background

Aristotle analyzed qualities in his logical work, the Categories. To him, qualities are hylomorphically–formal attributes, such as "white" or "grammatical". Categories of state, such as "shod" and "armed" are also non–essential qualities (katà symbebekós). Aristotle observed: "one and the selfsame substance, while retaining its identity, is yet capable of admitting contrary qualities. The same individual person is at one time white, at another black, at one time warm, at another cold, at one time good, at another bad. This capacity is found nowhere else... it is the peculiar mark of substance that it should be capable of admitting contrary qualities; for it is by itself changing that it does so". Aristotle described four types of qualitative opposites: correlatives, contraries, privatives and positives.

Quality (physics)

In response theory, the quality of an excited system is related to the number of excitation frequencies to which it can respond. In the case of a homogeneous, isotropic system, the quality is proportional to the FWHM.

This sense of the phrase is the precursor of the usage of the word in music theory. In music theory, quality is the number of harmonics of a fundamental frequency of an instrument (the higher the quality, the richer the sound).

See also

Quality (album)

Quality is the debut studio album by American rapper Talib Kweli. The album was released on November 19, 2002, by Rawkus Records. It received wide critical acclaim and had some commercial appeal from the song "Get By", produced by Kanye West. Kludge magazine included it on their list of best albums of 2002.

Track listing

Chart positions

References

External links