Design And Implementation Of Hardware Platform For Digital Hearing Aid With Microphone Array

Because of congenital defects or influence of environmental factors, the number of the people who are suffering from deafness in varying degrees is increaing year by year. Communication is an important means for individual’s social integration. There is no doubt that the deafness will impede the normal conduct of the communication, and patients will keep painful because of the deafness. Hearing aids, as effective treatment tools, have developed to the intelligent digital hearing aids. Digital hearing aids fitting the individual’s voice compensation curve by the microprocessor. But cassette hearing aids in china are mostly Low-end analog hearing aids.The paper proposes a kind of digital hearing aids with microphone array which is based on the ARM Cortex-A8 embedded platform. The digital hearing aids reduces cost and ensures the drive capacity of speech enhancement algorithm. The Cortex-A8 system is the core of this design and the structure of the microphone array provides a hardware basis for the speech enhancement algorithm with muiti channel. The paper talks about the background and significance of digital hearing aids simply, and explains the key technology of digital hearing aids briefly, such as working principle of digital hearing aid and microphone array topology. Then the paper introduces the embedded system for the design, and describes the hardware design structure, such as overall architecture design, microphone driver circuit design, audio buffer circuit design, audio decoding module,audio decoding module,power manage control module, serial ports and decoupling circuit design. The chip of each functional module is designed according to the functional requirements, and the circuit is built according to the chip’s user manual.Finally, the paper states the design in the printed circuit board. The PCB design includes circuit board layer selection,copper skin segmentation, Layout and routing. According to the basic principles of relevant design and actual situation of the digital hearing aid, the process of PCB design is described in detail. The function debug mainly measures power supply voltage and clock signal frequency, the data indicates that the performance of the circuit is successful. In addition, the system has reserved I2 S and GPIO interface, for its functional extension in the future.