1, true wireless stereo (TWS) is the main scheme of the new generation of wireless stereo headphones.
Real wireless stereo, the English vocabulary is True Wireless Stereo, referred to as TWS, it is a Bluetooth headset / sound box technology innovation, can realize the wireless separation of the Bluetooth voice channel.
The core principle of this technology is to divide speakers into main speakers (TWS Master) and subordinate speakers (TWS Slave). The main speaker is the audio of the A2DP protocol that can receive the smart phone, notebook and other devices (sound source), and the streaming media control signal of the AVRCP protocol, and transmit the audio to the speakers of other TWS devices. A slave loudspeaker is a loudspeaker that can receive A2DP protocol audio from the main speaker. Compared with high-end TWS headphones, two speakers can be used as main speakers.
TWS technology enables the audio of the mainstream A2DP protocol to be transmitted from the main speaker to the loudspeaker to synchronize the audio in the two separate speakers, and then the stereo effect is achieved.
Apple, Samsung, Jabra and other industry leaders have adopted TWS technology in new products. The typical representative of TWS headset is apple AirPods. Besides that, Samsung Gear IconX, Jabra Elite Sport are also representative products in the industry. Form 7, we summarize the TWS headphones that have been released by electronics giants and start-ups.
In addition to the whole machine, TWS's main solution provider, British chip manufacturer CSR, and two companies under NYK NXP, are both bought by high - pass, and a representative of the industry giants in the field of radio - Acoustic distribution.
Compared with the ordinary Bluetooth headset, the wireless headset with TWS technology has obvious advantages in portability, high-definition sound quality, volume, intelligent level, waterproof and so on.
2, with AirPods as the representative, the number and complexity of TWS earphone components have been greatly improved.
A pair of AirPods headphones and 1 charging devices have 28 main components and hundreds of components, which have greatly improved the number and complexity of components compared to previous wireless headphones.
In addition to components such as acoustic devices, decode chips, such as wireless headphones, AirPods integrates several different functional sensors to greatly improve the convenience of wireless headphones.
AirPods's new biometrics and noise reduction are mainly realized by various sensors. It mainly includes speech acceleration sensor, motion acceleration sensor, optical sensor and MEMS microphone.
Speech acceleration sensor:
The speech acceleration sensor is a voice activity detector that can feel the vibration produced by the user when speaking. The voice activity is detected by the user's muscle tissue and the vibration in the skeleton. The package size of the Bosch chip is 2.0mmx2.0mm x0.95mm.
Motion acceleration sensor: to achieve two functions of activating Siri and starting microphone.
The motion acceleration sensor in AirPods is derived from STMicroelectronics three axis accelerometer. With the use of optical sensors, it can generate many kinds of convenient functions. The package size is 2.50 mm x 2.50 mm x 0.86 mm.
Optical sensor: check whether the user is wearing a headset
The optical sensor in AirPods is made up of two photosensitive elements, combined with a motion acceleration sensor to detect whether you have put them in the ear, which automatically opens the functions of transmitting audio and activating the microphone. Its package size is 1.78 mm x 1.35 mm x 0.42 mm.
Microphone: call, voice input and background noise.
AirPods's MEMS microphones are all derived from GoerTek acoustics. A microphone using beamforming technology can be configured as an array to form a directional response or a beam field, which can be more sensitive to sound from one or more specific directions. With speech acceleration sensor, we can filter out background noise and clear the user's voice.
The battery inside the AirPods charger is a 3.81V, 1.52 watt lithium battery, which has about 16 times the capacity of the AirPods headset, and can fill two earphones with 8 times. In contrast, the battery of Apple Pencil is about 0.329 watts, and the Apple Watch Series 2 is 1.03 watt hour. So far, it is a capacity of * * micro battery.
In addition, we can see from more detailed disassembly diagrams that AirPods is not only a new addition of sensors, chips, acoustic devices, but also because of the increase in the number of components that lead to internal connectors (Speaker Connector, Antenna Connector, Button Connector, Charging Connector, Battery Pad, etc.), antennas, and antennas. The number of small parts, such as metal structural parts, has also increased greatly. It also raises higher requirements for the assembly and manufacturing capacity of the assembly manufacturers and the self-sufficiency of the metal components, forming a special high barrier for the TWS headset manufacturer.