Technical FAQs of TWS wireless headset factory

Whether it is Airpods or other TWS headsets, tws wireless headset factory believe that it can be said to be a product that conforms to the trend. In addition to avoiding the problem of removing the 3.5mm interface of the mobile phone, it needs to be equipped with an adapter cable. At the same time, it also enables one device for dual use (for example, some TWS headsets can wake up the AI voice assistant by double-clicking the left earphone, and double-click the right earphone to switch music and other operations. .) and other functions become possible.

However, due to the removal of the connection line (the connection line between the mobile phone and the connection line between the two earphones) of the TWS earphone, the two earphones form a stereo system through Bluetooth, which makes it also face great technical challenges. Among them, the most critical problem comes from the immature Bluetooth transmission scheme, and there are still some problems to be optimized, including the stability of signal transmission, which is susceptible to external signal interference; the main and auxiliary earphone signals are not synchronized; the sound quality is seriously damaged during transmission.

Of course, these problems have already existed in the previous Bluetooth headset solutions and have not been well resolved. They have been highlighted again in the promotion of TWS headsets. Therefore, they are also historical issues.

Classic scheme: The data signal is transmitted to the main earphone by the mobile phone using 2.4GHz Bluetooth signal, and then the signal is forwarded to the secondary ear by the main earphone as the 2.4GHz Bluetooth signal. The advantage of this kind of scheme is: use a set of radio frequency circuit, the PCB circuit board is small; the disadvantage is: 2.4GHz Bluetooth signal is easily absorbed by the human body, resulting in poor penetration (the most direct experience result is to cover the main body with one hand) Earphones, you can’t hear the sound from the pair of earphones), and are susceptible to interference from WiFi and other Bluetooth signals.

Binaural synchronous transmission scheme: The Bluetooth signal of the mobile phone is directly transmitted to two earphones in two ways, which can effectively avoid the problem of electric wave loss. Disadvantages: This kind of solution is not compatible with the mobile phone platform, and it is difficult to be compatible across chips. For example, headsets supported by Qualcomm chips are not compatible with mobile phones using Apple or Huawei HiSilicon chips. In addition, earphones using this type of solution are prone to binaural signal asynchrony.

LBRT magnetic induction forwarding scheme: first transmit the signal to the main earphone with a high-frequency Bluetooth signal, and then synchronize to the secondary earphone through the magnetic induction forwarding technology. In this way, the penetration of the signal is enhanced, the loss of sound quality can be avoided, and the delay can be reduced. The disadvantage is that more low-frequency antennas need to be added to the earphones. Such solutions are mostly used by current equipment manufacturers.

Equipped with AI voice function, into a voice pilot application

Although as early as 2011, the iPhone 4S released by Apple was equipped with the smart voice assistant Siri, but the mainstream human-computer interaction method for smart phones was still the touch method, and it failed to move forward to the voice method as desired. From the current point of view, smart phone manufacturers would rather continue to upgrade their cameras and focus on taking pictures, rather than picking up smart voice assistants as a selling point and spending a lot of money on promotion.

However, tws wireless headset factory believe that smart phone manufacturers are more willing to try to apply smart voice functions on TWS headsets as a voice pilot. In fact, this is completely understandable. After all, compared to the multi-scenario applications of smart phones, TWS headsets are more suitable for smart voice functions because they focus on voice application scenarios. Therefore, equipment manufacturers have also paid attention to and improved this function.

In March 2019, after 3 years, the second generation of Apple's Airpods also began to come out. The main control chip is upgraded from Apple W1 chip to Apple H1 earphone chip, and the performance has been greatly improved.

From the point of view of functional updates, a major change in the new AirPods is the activation method of AI voice: unlike the previous generation that requires two taps to activate Siri, the new generation can directly activate Siri through voice (wake-up word) and supports Chinese interaction. . Double-clicking AirPods is used to control playing songs or switch songs.

In addition, the new AirPods include a voice acceleration sensor that can recognize when the user is speaking and work with a pair of microphones using beamforming technology to filter out external noise to better receive the user's voice.

Re-AI voice is not only the idea of Apple (AirPods), it has also become one of the main selling points of current TWS headsets.