音頻信號分析儀設計

測控論文編號:CK096   論文字數:11603,頁數:32

 目 錄
摘要......................................................................III
一 前言....................................................................1
    1.1音頻信號及音頻分析....................................................1
    1.2選題的背景與意義......................................................1
    1.3音頻分析儀器現狀......................................................2
    1.4研究的基本內容與基本要求..............................................3
二 音頻信號分析儀的方案設計與論證..................................4
    2.1方案比較與選擇........................................................4
    2.2系統實現框圖..........................................................6
三 理論分析與計算.......................................................7
   3.1前級電路參數分析及A/D位數選擇.........................................7
   3.2采樣率及采樣點數確定...................................................7
   3.3功率譜測量方法.........................................................8
   3.4周期性判斷方法.........................................................9
   3.5失真度測量原理........................................................10
四 主要電路功能與實現................................................11
   4.1程控放大器的實現......................................................11
   4.2 A/D采樣..............................................................11
   4.3 濾波器的設計與實現...................................................12
   4.4總功率測量電路........................................................13
   4.5 FPGA部分.............................................................14
   4.6 單片機部分...........................................................14
五 系統軟件部分........................................................19
六 系統誤差分析........................................................21
七 結論...................................................................22
八 總結...................................................................23
致謝.......................................................................24
參考文獻..................................................................25
附錄.......................................................................27

摘  要
 本系統基于快速傅立葉變換(FFT)算法，以AT89S52單片機和FPGA為控制與數據處理核心，結合必要的外圍電路，實現對頻率范圍在200Hz~10KHz音頻信號頻率成分的分析 。以單片機為主要控制器件，由信號調節、信號采樣和DFT算法處理等部分組成。信號調節與12位A/D配合，保證了測量精度。信號采集后存儲到FPGA內部的RAM中，將旋轉因子量化存儲到FPGA的ROM中，利用地址發生器將采樣信號與旋轉因子在一定的時序下相乘累加，高速精度地完成了DFT算法。系統由控制與運算核心、程控放大器、濾波和采樣等模塊組成。通過對程控放大器增益的調整將系統可測電壓(峰-峰值)的動態范圍確定為100mV~5V； 通過改變模數轉換器的采樣頻率，實現頻率分辨力100Hz；頻譜分析結果可按序存儲，并使用點陣式液晶屏實時顯示；通過對頻譜數據特征的提取判斷信號的周期性，并實現對信號的失真度分析。另外，可通過點陣式液晶屏以圖形方式顯示信號各頻率分量及其相對大小。
關鍵詞：頻域分析、FFT、頻率分量、分辨力、周期性
 
Abstract
The system is based on fast Fourier transform (FFT) algorithm to AT89S52 MCU and FPGA for the control and data processing core, combined with the necessary external circuit, the frequency range of 200Hz ~ 10KHz audio signal frequency component analysis.To MCU as the main control device, the signal conditioning, signal processing, sampling andDFT algorithm components.Signal conditioning and 12-bit A / D with guaranteed accuracy.After signal acquisition to the FPGA's internal RAM memory in the rotation factor to quantify the ROM to store FPGA, the use of address generator and twiddle factor will be sampling the signal timing under certain multiply accumulate, high-speed precision DFT algorithm is completed.System control and operation by the core, programmable amplifiers, filtering, and sampling and other modules.Through the programmable gain amplifier to adjust the system can measure voltage (peak - peak) of the dynamic range defined as 100mV ~ 5V; by changing the ADC sampling frequency, to achieve frequency resolution 100Hz; spectrum analysis results can be stored sequentially,and use real-time dot matrix LCD display; by spectral data feature extraction determine the periodic signal, and to realize the distortion of the signal analysis.In addition, through the dot matrix LCD screen to graphically display the signal of each frequency component and its relative size.
Keywords: frequency domain analysis, FFT, frequency components, resolution, periodic