What Is A Stereo Bluetooth Headset
What is a stereo Bluetooth headset
1, what is the stereo Bluetooth headset?
Stereo Bluetooth headset is a popular saying that can use the Bluetooth headset and mobile phone connection, wireless way to enjoy the phone to play the stereo music. If you want to achieve this function, Bluetooth headset and sprinkle machine must support Bluetooth A2DP transmission protocol. The protocol specifies the use of Bluetooth asynchronous transmission channel, the transmission of high quality music file data protocol stack software and use. Simply put, through the A2DP can make two also support the Bluetooth audio transmission devices connected to each other, whether it is Bluetooth 1.1 or 1.2 version, can import and out CD quality (16bits, 44.1kHz) music. If any of them does not support A2DP, then the sound can only output Handsfree profile (8bits, 8KHz), that is, ordinary voice call monaural sound quality. Even if the headset is a dual ear plug design is also far from the real stereo! Currently support A2DP mobile phone mainly includes Samsung Bluetooth mobile phone, Nokia 6270, Sony Ericsson P990 and so on.
2, what is Bluetooth?
Bluetooth is a radio technology that supports short-range communications (typically within 10m) of the device. Wireless information exchange between many devices, including mobile phones, PDAs, wireless headsets, laptops, and related peripherals. Bluetooth standard is IEEE802.15, work in the 2.4GHz band, bandwidth of 1Mb / s.
"Bluetooth" (Bluetooth) was originally a unified kingdom in Denmark in the 10th century, he will be Sweden, Finland and Denmark together. With his name to name this new technical standards, with the situation will be divided into a torn apart. Bluetooth technology uses high-speed frequency hopping (FH, Frequency Hopping) and time division multiple access (TDMA, Time DivesionMuli-access) and other advanced technology, in close proximity to the cheapest digital devices (various mobile devices, fixed communications equipment, Computer and its terminal equipment, a variety of digital data systems, such as digital cameras, digital cameras, and even a variety of household appliances, automation equipment) was linked to the network. Bluetooth technology will be a unified bridge of the various peripheral interfaces in the network, eliminating the connection between devices and replacing them with wireless connections.
Bluetooth is a short-range wireless communication technology, electronic devices can be connected with each other through Bluetooth, eliminating the need for traditional wires. Through the wireless receiver on the chip, with Bluetooth technology, electronic products can be 10 meters away from each other, the transmission speed can reach 1 megabyte per second. In the past, the transmission technology of the infrared interface required the distance between the electronic devices in the line of sight, and now with the Bluetooth technology, such trouble can also be exempted.
Bluetooth (Bluetooth) is by Toshiba, Ericsson, IBM, Intel and Nokia in May 1998 jointly proposed short-range wireless digital communications technology standards. The goal is to achieve a maximum data transmission speed of 1Mb / s (effective transmission speed of 721kb / s), the maximum transmission distance of 10 meters, users do not have to apply to use 2.4GHz ISM (industrial, scientific, medical) frequency band, in its On the establishment of 79 channels with a bandwidth of 1MHz, with 1600 times per second to switch the frequency, hobbing method of spectrum diffusion technology to achieve the radio and television transceiver.
Bluetooth technology advantages: support for voice and data transmission; the use of radio technology, transmission range, can penetrate different substances and diffusion between substances; using frequency hopping spread spectrum technology, strong anti-interference, easy to eavesdropping; Restricted spectrum, theoretically, there is no interference problem; low power consumption; low cost. Bluetooth disadvantage: slow transmission speed. Bluetooth technical performance parameters: the effective transmission distance of 10cm ~ 10m, increase the transmission power can reach 100 meters, or even further. The transceiver operates at 2.45GHz and covers 79 channels (from 2.402GHz to 2.480GHz) separated by 1MHz. Data transmission technology using short packets, frequency hopping spread spectrum technology, 1600 times / sec, to prevent eavesdropping and to avoid interference; each time to send a packet, packet size from 126 ~ 287bit; packet content can contain data or voice, etc. Service information.
Data transfer bandwidth for synchronous connection can reach 32.6Kbps in each direction, close to 10 times the typical 56kb / s Modem analog connection rate, asynchronous connection allows a direction of data transfer rate of 721kb / s, for uploading or downloading, this In the opposite direction of the rate is 57.6kb / s; data transmission channel for leaving three concurrent synchronous voice channels, each bandwidth 64kb / s; voice and data can also be mixed in a channel, providing a 64kb / s synchronous voice Connection and an asynchronous data connection. Network connection using encryption technology, while using the password to verify the connection device can be at the same time with other seven devices constitute the Bluetooth micro-network (Piconet), a Bluetooth device can add 8 different micro-network, each micro-network were 1Mb / s transmission bandwidth, when more than two devices share a Channel, you can form a Bluetooth micro-network, and by one of the device-led transmission, when the device has not yet joined the Bluetooth micro-network, it first entered standby status.