Design Of BT620S Stereo Bluetooth Headset

Bluetooth technology is a kind of open global criterion for wireless data and audio communication,which bases on low cost and near end wireless connection,and establishes a seamless connection between immobility and mobile communication products.Nowadays,Bluetooth technology has been widely using in practical.Due to cell phone has a very high popularization,so the Bluetooth mobile phone is now becoming the main application for Bluetooth technology.Being as a accessory for mobile phone,the Bluetooth headset is getting more and more consumers' favorite,which depends on it's handy and safe characteristics.Therefore,How to design a kind of Bluetooth headset with powerful function,excellent performance and low cost is becoming a significant subject in the field of Bluetooth technology.This text is aiming to design a stereo Bluetooth headset which type is BT620S.The whole design process is being presented in detail from hardware,radio,software and acoustics.From electrical circuit,BT620S introduce BC3-MME Bluetooth solution.This solution is able to comply with Bluetooth 2.0 profile and A2DP stereo audio and some other functional requirements by using minimum peripheral components.And the low operating and standby power consumption allows BT620S is able to achieve up to 16 hours of talk time and 260 hours of standby time.BT620S is complied performance requirements after hardware verification tests,and it can meet ESD criterion.From RF design,BT620S is using a kind of inverted-F antenna by our independent design.It is a Bluetooth antenna being plated on PCB,according to antenna simulation and tuning.This kind of antenna doesn't only meet the requirement for Bluetooth radio specification,but also be provided with better reliability and uniformity without additional cost.By conducted and radiated verification,the RF performance for BT620S is able to comply with radio frequency specification requirement.Being applied the software development platform of protocol stack,function database and Bluelab that CSR provided,the software development process can be simplified and development resource can be saved as well.Users are able to directly implement functional setting,Software update and debugging.The functional tests and IOP test were designed for stereo Bluetooth headset particularly,it can find out up to 95%of software design errors. From acoustic design,BT620S is using dynamical loop Hi-Fi speakers and an omnidirectional microphone,which the range of receive frequency response is up to 100Hz-4KHz.The sound cavity design is to transform the geometric parameters and acoustic parameters of the sound cavity to electric parameters,and make the equi-circuit, simulate the circuit by Pspise afterwards,that we can get the RX and TX frequency response and sensitivity.We are adopting B&K 2012 audio analyzer system to perform acoustic test for BT620S.After verification test,the performance for BT620S on both receive path and transmit path are able to comply with the requirement for acoustic specification.Nowadays,BT620S stereo Bluetooth headset has already been coming into mass production,and the feedback from market is favorable.This product provides a typical design example for Bluetooth audio device,and the testing methods and processes provide a very high reference value for electrical communication products.