Transformer Sound Acquisition System Design And Realization Based The NiosⅡ

Ubiquitous nature of the sound, which consists of the mechanical vibration of thesound source, in the form of sound wave propagation medium. Characterized bycapturing audio signals, the sound source can get the status. With modern computertechnology, high-speed general-purpose computer systems, massive numericalcomputing and embedded computer systems to enhance the ability of intelligent controlobjects, making the sound signal high-speed, high-precision acquisition and analysispossible. Voice signal through the object-precision acquisition, conversion into digitalsignals, the computer now the spectral characteristics of high-speed computingcapability, thus achieving its status monitoring. This method is widely used in theproduction practice and scientific research, especially in the field of industrial control,the operating sound of the instrument signal monitoring of the safety of the productionprocess, equipment and product safety plays an important role. Therefore, the soundsignal of high-speed, high-precision acquisition has important significance. Currently,the market presence of the audio capture card capture slow, low precision audio range isnarrow, that is only in the frequency range of20Hz~20kHz characteristics, andprofessional audio capture device is expensive, can not meet the monitoringrequirements in general.To solve the above issues can be changed by the modulus of the two is an importantindicator of the sampling frequency and quantization precision to increase accuracy andspeed of the audio capture, the sampling frequency is the sound of the analog signalfrom the continuous and integral discrete signal extracted per seconds, the number ofsamples. According to sampling theory, the sampling frequency should not be less thantwice the highest frequency sound signals. Only by improving the sampling frequency,in order to ensure the sound is not distorted. So with the improvement of the highsampling frequency, the better the sound reduction, distortion, but the audio data is alsobecomes large. Quantization precision at each sampling point is the approximate value of the range, the degree of precision. Quantization bit number can be represented by theamplitude of the higher level of the more. Median sample size affect the sound quality,the more bits the higher the sound quality and need more storage space. In determiningthe number of channels of audio sounds an important indicator of the originalsingle-channel audio data is used to record a sound, multi-channel is defined by anumber of different channels to collect the original audio data, number of channels, themore energy reaction at different angles to the sound signal. After sampling, thequantized PCM data is the digital audio signals can be directly transmitted and stored inthe computer.In-depth study of modern digital audio technology, based on the transformer givenbased on sound collection NiosII sound collection system design, the main transformerprecision sound data collection, computer analysis of their work for the state to providethe data base. Transformer is working properly, due to alternating current through thetransformer coil electromagnetic force generated when silicon and the transformeritself to attract the vibration emitted sound. If uneven or other abnormal sound, areconsidered abnormal. The inspectors have been judged by the ear transformer isoperating normally, but the results vary. Through the transformer precision audio datacollection and the sound characteristics of the computer, to overcome the person as aresult of the shortcomings vary.This system is the core chip is launched with the support of Altera Corporation Nios IIfamily of soft-core CPU’s Cyclone III family FPGA: EP3C5E144. In Nios II soft-coreas the core, the use of FPGA logic resources to achieve the sound collection function ofeach module, constitute SOPC programmable system on chip, the system has a flexibledesign, support tailoring, expand, upgrade, and on the system hardware and softwareprogrammable functions, along with sufficient on-chip programmable logic resources,rich IP core resources are available. System through the Avalon bus, the realization ofeach module communication, the definition of SPI, SDRAM, UART, etc. IP core, aswell as prepare the SD card FAT16file system, to achieve a system-on-chip control,data caching, data storage capabilities. External AD section uses a dual-channel,24-bitprecision, the maximum sampling frequency up to192kHz AD converter PCM1804toachieve the sound signal acquisition, combined with an external amplifier, digital andanalog isolation circuit, the sound of the whole system of the transformer highAccuracy collection and storage, providing the back of the computer analysis.