Study On Digital Pocket Hearing Aids System Based On DSP

With the continuous improvement of quality of life, China has gradually entered the aging society, more and more patients with hearing loss use hearing aids.. In domestic market, analog devices play a main role in this field, and the amount of digital products is negligible. Therefore, based on DSP, this paper aims to design a digital pocket hearing aids, which produces a high-performance digital pocket hearing aids with low-cost, low-power consumption, small distortion, and high adjustability, and it surely has a promising future.In this digital pocket hearing aids, digital DSP chip is used as the core controller to achieve the noise reduction processing on the input source and wide dynamic range compression in order to ensure the output of different deaf people listening to the voice signal of the threshold range of the system, which based on the clarity of the voice and the natural conditions. This paper designs two kinds of digital chip-based hearing aid systems that each with BR261and BS300as cores, based on the market research and testing on digital pocket hearing aids, as well as the function of the market mainstream products, hardware design has been done according to the modular design, experimental analysis and the whole design of the program. After analysis and comparison tests, the type and power of the EEPROM, the MIC and other devices are determined according to the operating voltage, gained size and other parameters. Besides, the impact of voice channels and the model output on the machine are determined to achieve the hardware design and modification of the machine.Software design is used for parameters configuration of the software modules, and testing the hearing aid effect. The debugging of hardware and software reduced the basic functions of the hearing aid on the basis of experiments and improvements. Therefore, it fully meets the cassette machine products industry required standard, which are, to achieve a full sound gain of50dB, deviation of less than±4; maximum saturation sound pressure level of120dB, the deviation is less than±4; equivalent input noise is not greater than32dB; less than15%total harmonic distortion less than1KHz, less than10%greater than1KHz current is less than10mA, the lowest operating voltage less than1.5V.