The early non-Apple camp's TWS solution was the forwarding mode, that is, the mobile phone sent a two-channel audio signal, which was received by the main headset and then forwarded to the secondary headset. The scheme uses 2.4GHz Bluetooth signals to transmit audio, but the 2.4GHz frequency band is easily absorbed by the body, resulting in poor penetration and being easily interfered by WiFi and other Bluetooth signals. At the same time, due to the need for secondary forwarding, there is a large delay in audio playback, and the phenomenon of audio and picture is not synchronized. In addition, since the primary headset is responsible for forwarding signals, the power consumption is greater, and the uneven power consumption of the primary and secondary headsets also affects the user experience.
In order to solve the delay problem of the traditional forwarding mode, the leading domestic TWS headset chip manufacturer Heng Xuan launched the BES2300 series chip of Low Band Retransmission (LBRT) in 2018. The mobile phone will use a two-channel 2.4GHz Bluetooth audio signal It is sent to the main earphone, and the main earphone sends a low-frequency magnetic induction forwarding signal to the sub earphone through the magnetic induction coil. The traditional forwarding mode has high delay and poor penetration, while Hengxuan’s main low-frequency magnetic induction signal has good penetration and fast response, and is not easily interfered by other 2.4GHz signals. Therefore, the delay is low and it can avoid loss of sound quality. Hengxuan's LBRT forwarding solution can greatly reduce power consumption, and can be connected to various sensors and memories, but low-frequency antennas need to be added to the headphones.
Hengxuan's low-frequency forwarding solution bypasses Apple's patent blockade and provides a more cost-effective low-latency Bluetooth connection solution, which is used in Huawei Freebuds2 and Xiaomi TWS headphones. At the same time, this solution does not require the adaptation support of the mobile phone SoC, and can achieve better compatibility with different mobile phone platforms.Tags: Forwarding scheme
Post time: 2020-08-18