The Design Of Multimedia Speaker Audio Part Base On BC5Bluetooth Module

The intelligent terminal products, such as smart mobile phone, tablet computer have developed rapidly in recent years. Under the limited size, the sound quality of intelligent terminal always cannot satisfy the demand of consumer for music listening enjoyment. Because of its bulky shape and complicated connection, the traditional multimedia speakers cannot give consumers a better experience. The wireless speaker is a good solution. Among all the wireless technology, Bluetooth is the most technically matured and widely used.This paper mainly discusses the design of the audio part of the multimedia speaker based on BC5Bluetooth module. The MCU STM32F103is adopted as main controller in this system and it realizes the control of the audio signal input circuit and audio signal processing circuit; The wireless connection and wireless transmission of audio data between intelligent terminal and multimedia speaker are available by using the CSR BlueCore-5MM Bluetooth module; The Instant plug and play function of Music data such as MP3WMA AAC and WAV format which is Stored in the USB device is realized through the hardware decoding chip; The multimedia speaker has a good tune radio function in the64M to108M frequency by using the embedded FM radio module; Through comparing the excellence and the shortcoming of different kinds of the power Amplifier, the reason of choosing the class D Amplifier is that the class D Amplifier has high efficiency and little distortion and big output power and so on; In order to meet the needs of working voltage of the various parts of the circuit, this design adopts DC-DC voltage conversion chip to realize the conversion between the12v input voltage and working voltage, the DC-DC voltage conversion chip has the advantages of high conversion efficiency, large output current, quiescent current etc.The testing results show that the performance of the Multimedia Speaker base on BC5Bluetooth module in this paper is well. The power supply part can provide stable DC voltage and the ripple is small. The audio part can realize the various functions of the design requirement, and the electrical performance test data, such as frequency response, total harmonic distortion, channel separation or Crosstalk can meet the design requirements.