Bluetooth Low Energy, introduced in the 4.0 specification, uses the same spectrum but somewhat differently see Bluetooth low energy#Radio interface.In fact, Golden Ears, an audio equipment evaluation site, rated TONE ULTRA highly for its impressive audio performance. Packets may be 1, 3 or 5 slots long, but in all cases the master's transmission begins in even slots and the slave's in odd slots. The slave, conversely, receives in even slots and transmits in odd slots. In the simple case of single-slot packets the master transmits in even slots and receives in odd slots. Two clock ticks make up a slot of 625 µs, and two slots make up a slot pair of 1250 µs. Packet exchange is based on the basic clock, defined by the master, which ticks at 312.5 µs intervals. One master may communicate with up to seven slaves in a piconet. The combination of these (BR and EDR) modes in Bluetooth radio technology is classified as a "BR/EDR radio".īluetooth is a packet-based protocol with a master-slave structure.
The term Enhanced Data Rate (EDR) is used to describe π/4-DPSK and 8DPSK schemes, each giving 2 and 3 Mbit/s respectively. Devices functioning with GFSK are said to be operating in basic rate (BR) mode where an instantaneous data rate of 1 Mbit/s is possible. Since the introduction of Bluetooth 2.0+EDR, π/4-DQPSK (Differential Quadrature Phase Shift Keying) and 8DPSK modulation may also be used between compatible devices. Originally, Gaussian frequency-shift keying (GFSK) modulation was the only modulation scheme available. Bluetooth low energy uses 2 MHz spacing, which accommodates 40 channels. It usually performs 800 hops per second, with Adaptive Frequency-Hopping (AFH) enabled. Bluetooth divides transmitted data into packets, and transmits each packet on one of 79 designated Bluetooth channels. Bluetooth uses a radio technology called frequency-hopping spread spectrum. This is in the globally unlicensed (but not unregulated) Industrial, Scientific and Medical (ISM) 2.4 GHz short-range radio frequency band. The implication is that Bluetooth does the same with communications protocols, uniting them into one universal standard.īluetooth operates at frequencies between 24 MHz, or 24.5 MHz including guard bands 2 MHz wide at the bottom end and 3.5 MHz wide at the top. Bengtsson's historical novel The Long Ships about Vikings and King Harald Bluetooth. At the time of this proposal he was reading Frans G. The idea of this name was proposed in 1997 by Jim Kardach of Intel who developed a system that would allow mobile phones to communicate with computers. The name "Bluetooth" is an Anglicised version of the Scandinavian Blåtand/ Blåtann (Old Norse blátǫnn), the epithet of the tenth-century king Harald Bluetooth who united dissonant Danish tribes into a single kingdom and, according to legend, introduced Christianity as well. The specification is based on frequency-hopping spread spectrum technology. Nils Rydbeck tasked Tord Wingren with specifying and Jaap Haartsen and Sven Mattisson with developing. The purpose was to develop wireless headsets, according to two inventions by Johan Ullman, SE 8902098-6, issued and SE 9202239, issued. The development of the "short-link" radio technology, later named Bluetooth, was initiated in 1989 by Nils Rydbeck, CTO at Ericsson Mobile in Lund, Sweden, and by Johan Ullman. A network of patents apply to the technology, which are licensed to individual qualifying devices. A manufacturer must meet Bluetooth SIG standards to market it as a Bluetooth device. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks. The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. Invented by telecom vendor Ericsson in 1994, it was originally conceived as a wireless alternative to RS-232 data cables.īluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 30,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. Bluetooth is a wireless technology standard for exchanging data over short distances (using short-wavelength UHF radio waves in the ISM band from 2.4 to 2.485 GHz) from fixed and mobile devices, and building personal area networks (PANs).