Chirp

A chirp is a signal in which the frequency increases (up-chirp) or decreases (down-chirp) with time. In some sources, the term chirp is used interchangeably with sweep signal. It is commonly used in sonar and radar, but has other applications, such as in spread-spectrum communications. In spread-spectrum usage, surface acoustic wave (SAW) devices such as reflective array compressors (RACs) are often used to generate and demodulate the chirped signals. In optics, ultrashort laser pulses also exhibit chirp, which, in optical transmission systems, interacts with the dispersion properties of the materials, increasing or decreasing total pulse dispersion as the signal propagates. The name is a reference to the chirping sound made by birds; see bird vocalization.

Types

Linear

In a linear chirp, the instantaneous frequency varies linearly with time:

where is the starting frequency (at time ), and is the rate of frequency increase or chirp rate.

where is the final frequency and is the starting frequency. is the time it takes to sweep from to .

2 Chainz

Tauheed Epps (born September 12, 1977), better known by his stage name 2 Chainz (formerly Tity Boi), is an American rapper from College Park, Georgia. He initially gained recognition for being one-half of the Southern hip hop duo Playaz Circle, alongside his longtime friend and fellow rapper, Earl "Dolla Boy" Conyers. They are perhaps best known for being signed to fellow Georgia-based rapper Ludacris' Disturbing tha Peace label, as well as their debut single "Duffle Bag Boy".

In February 2012, Epps signed a solo record deal with Def Jam Records, an imprint of Universal Music Group. The following August, he released his debut studio album Based on a T.R.U. Story, to mixed reviews. The album spawned three successful singles: "No Lie", "Birthday Song", and "I'm Different", all of which charted in the top 50 of the Billboard Hot 100 and were certified Gold or higher by the RIAA, along with the album being certified Gold. His second studio album B.O.A.T.S. II: Me Time was released on September 11, 2013. It was supported by the singles "Feds Watching", "Where U Been?", and "Used 2".