DSP Hardware Implementation Of Acoustic Echo Cancellation

In recent years, with the rapid development of communication technology, a variety of communication methods enter into our life, greatly facilitate the communication between people, and people's demand for the quality of the communication is also constantly improving. When we driving in the car, or when we taking a call with not releasing our hands, this time hands-free call can provide a great convenience for people. In television and telephone conference, hands-free telephone system, hands-free calls are used more widely. But when people enjoy the convenience of hands-free calls at the same time, there will be a disturbances generated by the acoustic echo, for example, when we take a hands-free call, we will hear ourselves echo and this will affect the communication quality. Therefore, in recent years, solving the acoustic echo in hands-free voice call system is a hot issue. A way that we eliminate acoustic echo is simulating an echo signal through the adaptive algorithm and Subtracting the input signal from the speech signal so as to eliminate the echo signal.The paper introduces the mechanism of acoustic echo and introduces the basic method of acoustic echo cancellation and introduces the basic principle of acoustic echo cancellation algorithm and introduces the derivation process and basic principle of LMS algorithm and analyzes the convergence rate of the algorithm and introduces the adaptive filter and a DSP hardware system is constructed to realize the acoustic echo cancellation.The paper uses one of the 2000 series DSP, TMS320F28335 DSP of the United States TI Company to control the whole hardware system. The hardware platform of the echo cancellation is constructed by TI TLV320AIC23B.The connector between the DSP and the audio encoder is McBSP interface and we have used the DSP internal two channels DMA to allow data to be quickly shifting to DSP internal buffer. The audio encoder's AD converts the analog audio signal into a digital signal and sends the digital signal to DSP and the DSP executes the adaptive filtering algorithm and estimates echo signal and Then the estimation to the echo signal subtracts the input signal thereby eliminating off the echo signal, and then the audio data is sent to the audio encoder DA to output, thus completing the acoustic echo cancellation.In the hardware circuit we also set a RJ11, a handle interface when we do not use hands-free function we could use the handle calls. Secondly, in order to use PC control of the hardware system, we set a USB interface and the USB transfer serial chip could convert the UART interface of DSP to USB.In the end, the paper introduces the whole hardware system test, the test data of the hardware system is shown in the form of a chart. The hardware system was tested in two different rooms through the local network to build real communication environment, through the LAN chat software named "FeiQiu".