Design And Research Of Digital Audio Processing System Based On NiosⅡ

In the current, analog audio processing technology is gradually replaced by digital audioprocessing technology. With the development and improvement of information technology,the digital audio processing technology has obtained a rapid development and it is graduallymoving toward the direction of higher processing speed and higher work efficiency and moreeconomic. The core of digital audio processing technology is the design of digital filter and itseffect is to transform collected audio signal in accordance with a certain algorithm. Then get ameet therequirementof the output signal which useful frequency component is reserved.Digital filtering plays an important role in the digital signal processing technology, which isalso an integral part in the entire DSP technology. According to the principle of the digitalfilter, the internal structure of digital filter is quite complex, which use a lot of multipliers,accumulators and logical arithmetic unit. Thus, the internal structure and the volume and theefficiency of the system greatly restrict the design of the conventional digital audio processingsystem. Along with the technological innovation of ASIC, the embedded technology has beengreatly improved. Therefore, the FPGA has obvious superiority in terms of performance,flexibility and power consumption. In this context, using programmable logic devices torealize digital filter in the digital audio signal processing has become a new research hotspot.The thesis has carried on the design and research to a digital audio processing on thebasis of Nios Ⅱ. By means of referring to large amount of information about the method ofimplementation and the application of the digital audio signal processing system, especiallystudy the digital signal filtering algorithm. Designing a kind of basing on SOPC technologyfor a digital audio signal processing system on chip, which using Altera company DE2development board as development platform and integrating DSP Builder and Quartus as themian software development environment.First of all, the system uses NiosⅡ soft core processor as a general controller topre-process input data of audio by the method of all-phase digital signal processing. Thepurpose is to reduce the error of the audio signal.In this novel, using an algorithm whichbased single window phase pretreatment audio data pre-processing. It can be clearly seenfrom the results that after the truncation processing signal waveform are same smoothing.Within a specific time frame, the waveform without distortion, and the statisticalcharacteristics (Autocorrelation function, Meanvalue, Variance) of the system function isstable and truncation error is reduced a lot. Secondly, the core of this thesis is based on theimprovement of the traditional ⅡR digital filter algorithm and presenting and designing a newmethod of digital filter algorithm. It is based on butterworth low-passfilter which propose that a combination of hardware and software implementations using large-scale programmablelogic devices FGPA system on a chip (SOPC). The system uses the Nios Ⅱ soft coreprocessor as the central control terminal to take the output data of the preprocessing moduleinto the filtering function module as input data and filter the digital audio signal afterpretreatment. The system results prove that the multi-channel parallel processing system iscorrect, efficient, economic and viable.Finally, using simulation software to test and verify the effect of filtering, which resultsshow that the digital audio signal processing system has been improved. It is a beneficialattempt for SOPC technology to realize digital audio processing systerm.