Bluetooth Communication Interface Design For Multifunctional Electroacoustic Testing System

Aiming at the defect of multifunctional electroacoustic testing system cannot test the Bluetooth electroacoustic equipment,carried out a series of improvements,and put forward a viable solution to some technical problems encountered in the development process of electroacoustic testing system.The multifunctional electroacoustic tester is improved.These improvements include changing the USB HID(Universal Serial Bus Human Interface Device)communication mode to a stable and fast USB serial port(Universal Serial Bus to Serial UART Interface)communication mode;the DC control module of the output channel has been designed,and the experiment proves that the DC bias of the output channel can be controlled within 0.1mV by closed-loop control;the design of power amplifier module has been improved,and experiment proves that through these improvements,the power frequency electromagnetic interference noise of the output channel has been successfully eliminated,and the thermal noise has been reduced.The audio interface that is more suitable for electroacoustic testing system than professional sound card is designed.The computer can communicate with audio interface through USB CDC(Universal Serial Bus Communication Device Class)protocol.Experiments show that the parameters,amplitude-frequency characteristics of input and output channels of audio interface,THD+N(Total Harmonic Distribution+Noise)of output channels and SNR(Signal to Noise Ratio)of input channels,are superior to professional sound cards,and complete synchronization of recording and playing is achieved.The Bluetooth communication interface for electroacoustic testing system is designed.The computer can communicate with it through USB HID protocol,monitor its running status,control the connection of Bluetooth electroacoustic equipment and the choice of audio protocol,and transmit audio data with it through USB Audio protocol.The management module of communication equipment is designed,which makes various devices with different communication modes,using USB to Serial UART Interface,USB CDC,USB Audio,USB HID,communicate efficiently and steadily under the control of the same PC software,thus forming a Bluetooth electroacoustic testing system.The new method to realize synchronous recording,impulse signal marking method,is designed.The synchronization of recording and playing between the audio interface and the Bluetooth electroacoustic equipment is realized.This paper contains 81 figures,4 tables and 52 references.