《DSP原理及应用》课程小论文.doc

DSP原理及应用课程小论文 学 院: 专业班级: 学生姓名: 学 号: 论文题目:_基于TMS320DSP的FIR滤波器的设计与实现 完成日期： 2014 年 6 月 10 日 指导教师评语: _ _ _ _ 成绩（五级记分制）:_ _ 指导教师（签字）:_ _ 一、引言二、 设计目的三、设计要求四、 总体设计4.1 CCS环境下FIR滤波器的设计及软件仿真4.1.1 程序流程图4.1.2 在CCS集成开发环境下新建FIR滤波器工程4.1.3观察滤波前后的信号的时域波形及FFT Magnitude波形4.1.4 程序清单4.2 对实时采样信号进行滤波的FIR滤波器的实现4.2.1 程序清单4.2.2 测试效果4.2.3 SCI串行数据传输五、 总结六、参考文献一、引言随着信息和数字技术的发展，数字信号处理已成为当今极其重要的学科和技术领域之一。在数字信号处理的基本方法中，通常会涉及到变换、滤波、频谱分析、调制解调和编码解码等处理。其中，滤波是应用非常广泛的一个环节，数字滤波器的理论与相关设计也一直都是人们研究的重点之一。FIR滤波器的是非递归的，稳定性好，精度高；更重要的是，FIR滤波器在满足幅频响应要求的同时，可以获得严格的线性相位特征。因此，它在高保真的信号处理，如数字音频、图像处理、数据传输和生物医学等领域得到广泛应用。数字滤波器根据其冲激响应函数的时域特性，可分为无限长冲激响应(I-IR)滤波器和有限长冲激响应(FIR )滤波器。FIR滤波器具有严格的相位特性，同时系统函数的极点固定在原点上，因而该类型的滤波器是稳定的。在数字信号处理中，滤波占有极其重要的地位。用DSP芯片实现数字滤波除了具有稳定性好、精确度高、不受环境影响等优点外，还具有灵活性好等特点2、 设计目的 （1）掌握用窗函数法设计FIR滤波器的原理及方法。（2） 掌握TMS320F2812 DSP处理器开发的程序框架结构，学习驱动TMS320F2812 DSP处理器程序编写并能使其正常工作。（3） 掌握使用TMS320F2812 DSP处理器实现FIR数字低通滤波器的设计方法。三、设计要求1、在CCS集成开发环境下，利用第1步得到的滤波器参数，利用窗函数法设计FIR滤波器程序，观察输入信号及滤波后得到的输出信号的时域波形；2、利用TMS320F2812的ADC片内外设的外围电路实时采集的混频信号数据，使用1个51阶的FIR低通滤波器，在CCS中设计FIR滤波器程序实现滤波，观察相关波形及滤波效果，通过SCI接口将数据传送到计算机上；4、 总体设计4.1 CCS环境下FIR滤波器的设计及软件仿真4.1.1 程序流程图 初始化 输入低通滤波器各频率参数 构建滤波器频域特性波形参数 使用FDATool提取滤波器参数或用FIR滤波器计算程序计算得到滤波器参数 构建FIR滤波器进行滤波 无限循环4.1.2 在CCS集成开发环境下新建FIR滤波器工程（）实验准备 设置软件仿真模式，启动CCS。（）建立工程 建立一个文件夹，存放在D:FIR，将D:课程设计FIR滤波器Fir源程序文件夹下的工程全部复制到D:FIR，在CCS中打开D:FIRfirfir.pjt工程，就会得到如图6所示的工程界面。FIR工程示例（）编译生成fir.out文件，通过File-Load Program装载该文件。4.1.3观察滤波前后的信号的时域波形及FFT Magnitude波形 （4）设置时域观察窗口选择菜单ViewGraphTime/Frequency，进行如图所示设置。输入数据时域波形和滤波后输出波形观察（）设置频域观察窗口，选择菜ViewGraphTime/Frequency ， （6）运行并观察结果。 选择Debug菜单的Run项，或按F5键运行程序。观察到的图形如图所示。4.1.4 程序清单 /#include DSP281x_Device.h / DSP281x Headerfile Include File/#include DSP281x_Examples.h / DSP281x Examples Include File/#include f2812a.h#includemath.h#define FIRNUMBER 25/#define SIGNAL1F 1000/#define SIGNAL2F 4500/#define SAMPLEF 10000#define PI 3.1415926float InputWave();float FIR();float fHnFIRNUMBER= 0.0,0.0,0.001,-0.002,-0.002,0.01,-0.009,-0.018,0.049,-0.02,-0.11,0.28,0.64,0.28,-0.11,-0.02,0.049,-0.018,-0.009,0.01,-0.002,-0.002,0.001,0.0,0.0 ;float fXnFIRNUMBER= 0.0 ;float fInput,fOutput;float fSignal1,fSignal2;float fStepSignal1,fStepSignal2;float f2PI;int i;float fIn256,fOut256;int nIn,nOut;main(void) nIn=0; nOut=0;f2PI=2*PI;fSignal1=0.0;fSignal2=PI*0.1;fStepSignal1=2*PI/30;fStepSignal2=2*PI*1.4;while ( 1 )fInput=InputWave();fInnIn=fInput;nIn+; nIn%=256;fOutput=FIR();fOutnOut=fOutput;nOut+;if ( nOut=256 )nOut=0; float InputWave()for ( i=FIRNUMBER-1;i0;i- )fXni=fXni-1;fXn0=sin(fSignal1)+cos(fSignal2)/6.0;fSignal1+=fStepSignal1; if ( fSignal1=f2PI )fSignal1-=f2PI;fSignal2+=fStepSignal2;if ( fSignal2=f2PI )fSignal2-=f2PI;return(fXn0);float FIR()float fSum;fSum=0;for ( i=0;iFIRNUMBER;i+ )fSum+=(fXni*fHni);return(fSum);4.2 对实时采样信号进行滤波的FIR滤波器的实现4.2.1 程序清单#include DSP281x_Device.h / DSP281x Headerfile Include File#include DSP281x_Examples.h / DSP281x Examples Include File#include #define pi 3.1415927int px256;int py256;double npass,h51, x, y, xmid51;int m=50;int n=256;/ Prototype statements for functions found within this errupt void adc_isr(void);/ Global variables used in this example:Uint16 LoopCount;Uint16 ConversionCount;void firdes(int m, double npass) int t; for (t=0; t=m; t+) ht = sin(t-m/2.0)*npass*pi)/(pi*(t-m/2.0); if (t=m/2) ht=npass; void main(void) int xm,ym; double fs,fstop,r,rm; int i,j,p,k;/ PLL, WatchDog, enable Peripheral Clocks/ This example function is found in the DSP281x_SysCtrl.c file. InitSysCtrl();/ For this example, set HSPCLK to SYSCLKOUT / 6 (25Mhz assuming 150Mhz SYSCLKOUT) EALLOW; SysCtrlRegs.HISPCP.all = 0x3; / HSPCLK = SYSCLKOUT/6 EDIS; / Disable CPU interrupts DINT;/ Initialize the PIE control registers to their default state. InitPieCtrl();/ Disable CPU interrupts and clear all CPU interrupt flags: IER = 0x0000; IFR = 0x0000;/ Initialize the PIE vector table with pointers to the shell Interrupt / Service Routines (ISR). InitPieVectTable();/ Interrupts that are used in this example are re-mapped to/ ISR functions found within this file. EALLOW; / This is needed to write to EALLOW protected register PieVectTable.ADCINT = &adc_isr; EDIS; / This is needed to disable write to EALLOW protected registersInitAdc(); / For this example, init the ADC/ Enable ADCINT in PIE PieCtrlRegs.PIEIER1.bit.INTx6 = 1; IER |= M_INT1; / Enable CPU Interrupt 1 EINT; / Enable Global interrupt INTM ERTM; / Enable Global realtime interrupt DBGM LoopCount = 0; ConversionCount = 0; / Configure ADC AdcRegs.ADCTRL1.bit.SEQ_CASC = 1; AdcRegs.ADCMAXCONV.all = 0x0000; / Setup 2 convs on SEQ1 AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x4; / Setup ADCINA0 as 1st SEQ1 conv. AdcRegs.ADCTRL2.bit.EVA_SOC_SEQ1 = 1; / Enable EVASOC to start SEQ1 AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1; / Enable SEQ1 interrupt (every EOS)/ Configure EVA/ Assumes EVA Clock is already enabled in InitSysCtrl(); EvaRegs.T1CMPR = 0x0380; / Setup T1 compare value EvaRegs.T1PR = 0x07FF; / Setup period register EvaRegs.GPTCONA.bit.T1TOADC = 1; / Enable EVASOC in EVA EvaRegs.T1CON.all = 0x1042; / Enable timer 1 compare (upcount mode)/ Wait for ADC interrupt k=0; fs = 250000; fstop = 20000; npass = fstop/fs; for (i=0; i=m; i+) xmidi=0; for(;) firdes(m, npass);for (i=0; i=n-1; i+) xm = pxi; x = xm/1023.0; for (p=0; p=m; p+) xmidm-p = xmidm-p-1; xmid0 = x; r = 0; rm= 0; for (j=0; j4; if(ConversionCount = 256) ConversionCount = 0; else ConversionCount+; / Reinitialize for next ADC sequence AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1; / Reset SEQ1 AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1; / ClearINT SEQ1 bit PieCtrlRegs.PIEACK.all = PIEACK_GROUP1; / Acknowledge interrupt to PIE return;4.2.2 测试效果如上图所示，可以发现使用DSP芯片实现的的FIR滤波器已经成功的将设定的混合频率信号中的高频部分滤除。4.2.3 SCI串行数据传输对实时采样信号进行滤波并通过SCI串口数据传输到计算机的程序如下： #include DSP281x_Device.h / DSP281x Headerfile Include File#include DSP281x_Examples.h / DSP281x Examples Include File#include #define pi 3.1415927int px256;int py256;double npass,h51, x, y, xmid51;int m=50;int n=256;long int delays; / Prototype statements for functions found within this errupt void adc_isr(void);void scia_init(void);void scia_xmit(char a);/ Global variables used in this example:Uint16 LoopCount;Uint16 ConversionCount;void firdes(int m, double npass) int t; for (t=0; t=m; t+) ht = sin(t-m/2.0)*npass*pi)/(pi*(t-m/2.0); if (t=m/2) ht=npass; void main(void) int xm,ym; double fs,fstop,r,rm; int i,j,p,k;/ PLL, WatchDog, enable Peripheral Clocks/ This example function is found in the DSP281x_SysCtrl.c file. InitSysCtrl();/ For this example, set HSPCLK to SYSCLKOUT / 6 (25Mhz assuming 150Mhz SYSCLKOUT) EALLOW; SysCtrlRegs.HISPCP.all = 0x3; / HSPCLK = SYSCLKOUT/6 EDIS; / Disable CPU interrupts DINT;/ Initialize the PIE control registers to their default state. InitPieCtrl();/ Disable CPU interrupts and clear all CPU interrupt flags: IER = 0x0000; IFR = 0x0000;/ Initialize the PIE vector table with pointers to the shell Interrupt / Service Routines (ISR). InitPieVectTable();/ Interrupts that are used in this example are re-mapped to/ ISR functions found within this file. EALLOW; / This is needed to write to EALLOW protected register PieVectTable.ADCINT = &adc_isr; EDIS; / This is needed to disable write to EALLOW protected registers InitAdc(); / For this example, init the ADC scia_init(); EALLOW; GpioMuxRegs.GPFMUX.all = 0x0030; /配置IO口为专用引脚 EDIS;/ Enable ADCINT in PIE PieCtrlRegs.PIEIER1.bit.INTx6 = 1; IER |= M_INT1; / Enable CPU Interrupt 1 EINT; / Enable Global interrupt INTM ERTM; / Enable Global realtime interrupt DBGM LoopCount = 0; ConversionCount = 0;/ Configure ADC AdcRegs.ADCTRL1.bit.SEQ_CASC = 1; AdcRegs.ADCMAXCONV.all = 0x0000; / Setup 2 convs on SEQ1 AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x4; / Setup ADCINA0 as 1st SEQ1 conv. AdcRegs.ADCTRL2.bit.EVA_SOC_SEQ1 = 1; / Enable EVASOC to start SEQ1 AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1; / Enable SEQ1 interrupt (every EOS)/ Configure EVA/ Assumes EVA Clock is already enabled in InitSysCtrl(); EvaRegs.T1CMPR = 0x0380; / Setup T1 compare value EvaRegs.T1PR = 0x07FF; / Setup period register EvaRegs.GPTCONA.bit.T1TOADC = 1; / Enable EVASOC in EVA EvaRegs.T1CON.all = 0x1042; / Enable timer 1 compare (upcount mode)/ Wait for ADC interrupt k=0; fs = 250000; fstop = 20000; npass = fstop/fs; for (i=0; i=m; i+) xmidi=0; for(;) SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55; SciaRegs.SCITXBUF=0x55;/帧首分隔符 firdes(m, npass);for (i=0; i=n-1; i+) xm = pxi; x = xm/1023.0; for (p=0; p=m; p+) xmidm-p = xmidm-p-1; xmid0 = x; r = 0; rm= 0; for (j=0; j=m; j+) r = xmidj * hj;rm = rm + r; y = rm; ym = (int)(1023.0 * y); pyi = ym; for(i=0;i256;i+) SciaRegs.SCITXBUF=pyi; for(delays=0;delays4; if(ConversionCount = 256) ConversionCount = 0; else ConversionCount+; / Reinitialize for next ADC sequence AdcRegs.ADCTRL2.bit.RST_SEQ1 = 1; / Reset SEQ1 AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1; / Clear INT SEQ1 bit PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;