Lights flash at frequency f = 0.5 Hz (Hz = hertz), 1.0 Hz and 2.0 Hz, where Failed to parse (Missing texvc executable; please see math/README to configure.): x

Hz means Failed to parse (Missing texvc executable; please see math/README to configure.): x
flashes per second. T is the period and T = Failed to parse (Missing texvc executable; please see math/README to configure.): y
s (s = second) means that Failed to parse (Missing texvc executable; please see math/README to configure.): y

is the number of seconds per flash. T and f are each other's reciprocal: f = 1/T and T = 1/f.

The hertz (symbol Hz) is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon.^[1] One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications. The word "hertz" is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence of electromagnetic waves.

Definition[link]

The hertz is equivalent to cycles per second.^[2] In defining the second, the CIPM declared that "the standard to be employed is the transition between the hyperfine levels F = 4, M =  0 and F = 3, M = 0 of the ground state 2S_1/2 of the cesium 133 atom, unperturbed by external fields, and that the frequency of this transition is assigned the value 9 192 631 770 hertz"^[3] thereby effectively defining the hertz and the second simultaneously.

In English, hertz is used as a plural.^[4] As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 10³ Hz), MHz (megahertz, 10⁶ Hz), GHz (gigahertz, 10⁹ Hz) and THz (terahertz, 10¹² Hz). One hertz simply means "one cycle per second" (typically that which is being counted is a complete cycle); 100 Hz means "one hundred cycles per second", and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz. The "frequency" (activity) of aperiodic or stochastic events, such as radioactive decay, is expressed in becquerels.

Even though angular velocity, angular frequency and hertz all have the dimensions of 1/s, angular velocity and angular frequency are not expressed in hertz,^[5] but rather in an appropriate angular unit such as radians per second. Thus a disc rotating at 60 revolutions per minute (rpm) is said to be rotating at either 2π rad/s or 1 Hz, where the former measures the angular velocity and the latter reflects the number of complete revolutions per second. The conversion between a frequency f measured in hertz and an angular velocity ω measured in radians per second are:

Failed to parse (Missing texvc executable; please see math/README to configure.): \omega = 2\pi f \,

and Failed to parse (Missing texvc executable; please see math/README to configure.): f = \frac{\omega}{2\pi} \, 

. This SI unit is named after Heinrich Hertz. As with every International System of Units (SI) unit whose name is derived from the proper name of a person, the first letter of its symbol is upper case (Hz). When an SI unit is spelled out in English, it should always begin with a lower case letter (hertz), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Note that "degree Celsius" conforms to this rule because the "d" is lowercase. —Based on The International System of Units, section 5.2.

History[link]

The hertz is named after the German physicist Heinrich Hertz who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1930.^[6] It was adopted by the General Conference on Weights and Measures (CGPM) (Conférence générale des poids et mesures) in 1960, replacing the previous name for the unit, cycles per second (cps), along with its related multiples, primarily kilocycles per second (kc/s) and megacycles per second (Mc/s), and occasionally kilomegacycles per second (kMc/s). The term cycles per second was largely replaced by hertz by the 1970s.

The term "gigahertz", most commonly used in computer processor clock rates and radio frequency (RF) applications, can be pronounced either /ˈɡɪɡəhɜrts/, with a hard /ɡ/ sound, or /ˈdʒɪɡəhɜrts/, with a soft /dʒ/^[7] (see giga-#Pronunciation). The prefix "giga-" is derived directly from the Greek "γιγας" ("giant").

Applications[link]

Sine waves of different frequency.

Details of a heartbeat as an example of a non-sinusoidal periodic phenomenon that can be described in terms of hertz. Two complete cycles are illustrated.

Vibration[link]

Sound is a traveling wave which is an oscillation of pressure. Humans perceive frequency of sound waves as pitch. Each musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz.^[8] The range of ultrasound, high-intensity infrasound and other physical vibrations such as molecular vibrations extends into the megahertz range and well beyond.

Electromagnetic radiation[link]

Electromagnetic radiation is often described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz.

Radio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens (infrared) to thousands (ultraviolet) of terahertz. Electromagnetic radiation with frequencies in the low terahertz range, (intermediate between those of the highest normally usable radio frequencies and long-wave infrared light), is often called terahertz radiation. Even higher frequencies exist, such as that of gamma rays, which can be measured in exahertz. (For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies: for a more detailed treatment of this and the above frequency ranges, see electromagnetic spectrum.)

Computing[link]

In computing, most central processing units (CPU) are labeled in terms of their clock rate expressed in megahertz or gigahertz (10⁶ or 10⁹ hertz, respectively). This number refers to the frequency of the CPU's master clock signal ("clock rate"). This signal is simply an electrical voltage which changes from low to high and back again at regular intervals. This signal is a square wave. Hertz has become the primary unit of measurement accepted by the general populace to determine the performance of a CPU, but many experts have criticized this approach, which they claim is an easily manipulable benchmark.^[9] For home-based personal computers, the CPU has ranged from approximately 1 megahertz in the late 1970s (Atari, Commodore, Apple computers) to up to 6 GHz in the present (IBM POWER processors) and up to 8 GHz overclocked (AMD FX processors).^[10]

Various computer buses, such as the front-side bus connecting the CPU and northbridge, also operate at different frequencies in the megahertz range

[edit] SI multiples

Frequencies not expressed in hertz[link]

Even higher frequencies are believed to occur naturally, in the frequencies of the quantum-mechanical wave functions of high-energy (or, equivalently, massive) particles, although these are not directly observable, and must be inferred from their interactions with other phenomena. For practical reasons, these are typically not expressed in hertz, but in terms of the equivalent quantum energy, which is proportional to the frequency by the factor of Planck's constant.

See also[link]

References[link]

External links[link]

• BIPM Cesium ion f_Cs definition
• National Research Council of Canada: Generation of the Hz
• National Research Council of Canada: Cesium fountain clock
• National Physical Laboratory: Trapped ion optical frequency standards
• National Research Council of Canada: Optical frequency standard based on a single trapped ion
• National Research Council of Canada: Optical frequency comb
• One Hertz in Radians per Second (Google). Note, as of 06 May 2009 there is an error of 2Failed to parse (Missing texvc executable; please see math/README to configure.): \pi

.

v t e SI units Base units Ampere · Candela · Kelvin · Kilogram · Metre · Mole · Second Derived units Becquerel · Coulomb · Degree Celsius · Farad · Gray · Henry · Hertz · Joule · Katal · Lumen · Lux · Newton · Ohm · Pascal · Radian · Siemens · Sievert · Steradian · Tesla · Volt · Watt · Weber Accepted for use with SI Dalton (Atomic mass unit) · Astronomical unit · Day · Decibel · Degree Celsius · Degree of arc · Electronvolt · Hectare · Hour · Litre · Minute · Minute of arc · Neper · Second of arc · Tonne Atomic units · Natural units See also SI prefixes · Systems of measurement · Conversion of units · New SI definitions · History of the metric system Book:International System of Units  · Category:SI base units

Camu Tao (born Tero Smith, June 26, 1977 – May 25, 2008^[1]) was an American rapper and producer who was signed to the Definitive Jux label. He was a member of several groups: S.A. Smash (with fellow rapper Metro), the underground hiphop supergroup Weathermen, Central Services (with fellow producer El-P), and the music collective Cardboard City.

He was also part of Columbus, Ohio's MHz crew with Copywrite, RJD2, Jakki Tha MotaMouth & Tage Proto. Partnering with Cage to form The Nighthawks, the two crafted an album during a single-three day creative session.^[2]

Smith died on May 25, 2008, after a two-year battle with lung cancer.^[1] At the time of his death, he was producing a song for Cage's I Never Knew You EP and working on his first solo for Definitive Jux. On July 9, 2009, El-P announced via Twitter that the album, King of Hearts, was finished, and would be released on October 20, 2009.^[3] King of Hearts was released on August 17, 2010 by Definitive Jux in collaboration with Fat Possum Records along with a free download EP from Central Services.^[4] About the album, El-P said:

We all expected to get Camu in the studio and go as far as he wanted to go with the record. The songs are bare, but then again a lot of them are just what he wanted. A lot of them wouldn’t have changed much. Knowing Camu, he had a lot of talented musician friends he would have liked to have collaborated and have involved. I do think the album would have been different had he lived to complete it.

Aesop Rock, also on Definitive Jux, stated in a 2008 interview with The A.V. Club that his next album may contain "a couple of songs about my friend Camu."^[5]. El-P, founder of the defunct Definitive Jux label, dedicated his album Cancer 4 Cure to his memory.

Discography[link]

• Presents Blair Cosby's Cape Cod (Going For De Gold) (Smash Bros., 2004)^[6]
• Presents Blair Cosby's Cereal Carpens '97 Season
• Presents "Blair Cosby II: The Wali Era"
• King of Hearts (Definitive Jux, 2010)

With Central Services[link]

• Forever Frozen In Television Time (Definitive Jux, 2010)

With MHz[link]

• Table Scraps (2001, Man Bites Dog, 2009 Re-release)

With The Nighthawks[link]

• Nighthawks (Eastern Conference, 2002)

With S.A. Smash[link]

• Smashy Trashy (Definitive Jux, 2003)

Compilations[link]

• Definitive Swim (Definitive Jux / Williams Street, 2007) ("Plot for a Little")

Singles[link]

• "Hear Me Talking to You" (B.U.K.A. Entertainment, 2001)
• "Hold the Floor"/"Wireless" (Definitive Jux, 2001)
• "WMR" (Camu Tao & El-P)/"Homesickness"/"Life with Snarky Parker" (Despot) (Definitive Jux, 2004)

References[link]

External links[link]

• Camu Tao on Myspace
• Camu Tao Bio at Definitive Jux

Chuck Brown
Onstage, October 1, 2005
Background information
Born	(1936-08-22)August 22, 1936 Gaston, North Carolina
Origin	Washington, D.C.
Died	May 16, 2012(2012-05-16) (aged 75) Baltimore, Maryland
Genres	Funk, go-go
Occupations	Singer, musician, songwriter, record producer, guitarist
Instruments	Guitar
Years active	1960s–2012
Website	windmeupchuck.com
Notable instruments
Gibson ES-335 (blonde)[1]

Chuck Brown (August 22, 1936 – May 16, 2012) was a guitarist and singer who is affectionately called "the Godfather of Go-go".^[2] Go-go is a subgenre of funk music developed in and around Washington, D.C. in the mid and late 1970s. While its musical classification, influences, and origins are debated, Brown is regarded as the fundamental force behind the creation of go-go music.^[1]

Overview[link]

Brown's musical career began in the 1960s playing guitar with Jerry Butler and The Earls of Rhythm, joining Los Latinos in 1965. At the time of his death he was still performing music and was well known in the Washington, DC area. Brown's early hits include "I Need Some Money" and "Bustin' Loose". "Bustin' Loose" has been adopted by the Washington Nationals baseball team as its home run celebration song, and was interpolated by Nelly for his 2002 number one hit "Hot in Herre." Brown also recorded go-go covers of early jazz and blues songs, such as "Go-Go Swing" Duke Ellington's "It Don't Mean a Thing If Ain't Got That Swing", "Moody's Mood for Love", Johnny Mercer's "Midnight Sun", Louis Jordan's "Run Joe", and T-Bone Walker's "Stormy Monday".

He influenced other go-go bands such as Big G and The Backyard Band, Rare Essence, Experience Unlimited (EU), Little Benny and the Masters, and Trouble Funk.

The song "Ashley's Roachclip" from the Soul Searchers' 1974 album Salt of the Earth^[3] contains a famous drum break, sampled countless times in various other tracks.

In the mid-1990s, he performed the theme music of Fox's sitcom The Sinbad Show which later aired on The Family Channel and Disney Channel.

Brown played a blonde Gibson ES-335.^[1]

Personal life[link]

Brown resided in Brandywine, Maryland. He had daughters Cherita Whiting, KayKay and two sons, Wiley and Nekos Brown. Wiley is^[when?] a musician and football player at Virginia Tech. His son, Nekos, was a defensive end/linebacker for the Virginia Tech football team. While his son^[which?] was in college, Brown scheduled concerts and other appearances around the Hokies home schedule to ensure that he would never miss a game, and became a fixture at Lane Stadium. Following the Virginia Tech massacre, Brown stated in an interview that he was "absolutely devastated" by the tragedy, and cried every day for two weeks.^[4] In shows that followed, Brown would pause for a moment in prayer for the victims and their families before beginning his performance, and dedicated several shows to their memory.

Death[link]

Chuck Brown died on Wednesday, May 16, 2012, at Baltimore's Johns Hopkins Hospital of multiple organ failure including heart failure or heart problems. He was 75 years old. Several weeks prior to his death, he had postponed and canceled shows due to hospitalization for pneumonia.^[5][2]

Legacy[link]

Brown was considered a local legend in Washington, D.C., and appeared in television advertisements for the Washington Post and other area companies. The D.C. Lottery's "Rolling Cash 5" ad campaign features Chuck Brown singing his 2007 song "The Party Roll" in front of various D.C. city landmarks such as Ben's Chili Bowl.

Brown was the subject of the cover article in The Washington Post Magazine on October 4, 2009, entitled Chuck Brown's Long Dance.^[6] He received his first Grammy Award nomination in 2010 for Best R&B Performance By A Duo Or Group With Vocals for "Love" (with Jill Scott and Marcus Miller), from the album We Got This.

In 2009, the 1900 block of 7th Street NW, in Northwest Washington, DC between Florida Avenue and T Street was renamed "Chuck Brown Way" in his honor.

On September 4, 2011, Brown was honored by the National Symphony Orchestra, as the NSO paid tribute to Legends of Washington Music Labor Day concert - honoring Brown's music, as well as Duke Ellington and John Philip Sousa - with a free concert on the West Lawn of the Capitol. Brown and his band capped off the evening with a performance.

Discography[link]

• 1972: (as The Soul Searchers) We the People
• 1974: (as The Soul Searchers) Salt of the Earth
• 1978: Bustin' Loose
• 1980: Funk Express
• 1984: We Need Some Money
• 1986: Go Go Swing Live [Future Sounds Production]
• 1987: Any Other Way to Go?
• 1987: Live '87 - D.C. Bumpin' Y'all [live; double album]
• 1989: Trust Me: Live Pa Tape, Vol. 2 [Future Records & Tapes]
• 1990: Wind Me up Chuck, Vol. 3 [Raw Venture Records & Tapes]
• 1991: 90's Goin' Hard
• 1993: This Is a Journey into Time [live]
• 1995: Hah Man
• 1995: The Other Side - with Eva Cassidy (recorded in 1992 and released in 1995)
• 1997: Live Pa Tape
• 1998: Timeless
• 1999: The Spirit of Christmas
• 2001: Your Game...Live at the 9:30 Club
• 2002: Put Your Hands Up!
• 2005: Best of Chuck Brown (remastered)
• 2007: We are About The Business (Raw Venture Records)
• 2010: We Got This (Raw Venture Records)

See also[link]

• Anthony Harley
• Go-go music

Biography portal

References[link]

External links[link]

This article's use of external links may not follow Wikipedia's policies or guidelines. Please improve this article by removing excessive or inappropriate external links, and converting useful links where appropriate into footnote references. (May 2012)

• Official website
• Chuck Brown's oral history video excerpts at The National Visionary Leadership Project
• Photo Gallery of Chuck Brown & his band at the 9:30 Club, Washington DC
• "Chuck Brown: Go-Go Godfather's Gumbo", All Things Considered, 10 May 2006
• "Wind me up, Chuck", Jeff Chang, San Francisco Bay Guardian, June 2001
• "Chuck Brown," Nick Baily, Global Rhythm, August 2007
• "Still Soulful, Still Swinging, Still Ready to Bust Loose," Jon Pareles, The New York Times, April 21, 2007
• "Chuck Brown's Long Dance," Robin Rose Parker, The Washington Post Magazine, October 4, 2009
• findagrave memorial