DSP与matlab联合设计FIR滤波器2

设计FIR滤波器作业报告学号：姓名：设计FIR滤波器作业报告本设计主要内容是利用MATLAB验证设计思路并用CCS3.3仿真环境设计一个FIR滤波器，要求滤除给定的叠加正弦波的两个较高频分量。给定波形函数为：y=sin(2*pi*100*t)+sin(2*pi*250*t)+sin(2*pi*270*t)。设计思路：输入信号是频率为100Hz、250HZ、270Hz的合成正弦等幅信号，由于给定的谐波分量最高为270Hz，根据奈奎斯特准则，采样频率应大于最高频率分量的2倍，即大于2*270，故可以以600Hz的采样频率进行采样，即fs=600Hz。设计了一个截止频率为200Hz的低通滤波器，目的是通过所设计的低通bartlett滤波器将信号源中频率为200Hz以上的信号滤掉，留下频率为100Hz的信号，达到滤波的效果。利用MATLAB设计合适的滤波器实现滤波，然后得到其滤波器系数在CCS的simulator方式下编写滤波程序，调用波形数据，实现滤波，并观看滤波前后的信号波形图、频谱图，观察滤波达到预期效果。设计过程在MATLAB中进行算法验证MATLAB语言由于具有数值计算功能、符号计算功能、数据可视化功能、建模仿真可视化功能，使得MATLAB在命题构思、模型建立、仿真研究、假想验证、数据源可视化各环节起着强大的作用。因此在设计中必须先在MATLAB语言中设计一个FIR滤波器。本设计采用的是bartlett窗函数。下面是在MATLAB中设计的27阶FIR型bartlett滤波器程序：clearall; %请寄存器clf; %清屏N=256; %清数据点fs=600; %采样频率dt=1/fs; %采样时间间隔fort=1:Nf1=250;f2=100;f3=270;y(t)=(sin(2*pi*f1*t*dt)+sin(2*pi*f2*t*dt)+sin(2*pi*f3*t*dt));%产生合成信号x(t)=round(10000*y(t)); %为DSP汇编程序做数据转换endfigure(1)plot(y),title('滤波前的波形图像');fp=200fst=250NL=26f1=200;w1=2*pi*f1/fswindow=bartlett(NL+1) %窗函数n=1:NL+1hd=sin(w1*(n-NL/2))./(pi*(n-NL/2));hd(NL/2)=0.67;h=hd.*rot90(window)h1=h*32768;h2=fft(h,N); %将信号做FFT变换pyy=h2.*conj(h2); %做功率谱分析f=(0:(N/2-1));fori=1:N/2-1f(i)=f(i)*fs/N;endfigure(2)plot(f,pyy(1:N/2)),title('滤波器的频谱图像');yy1=filter(h,1,y); %滤波figure(3)plot(yy1),title('滤波后的波形图像');y=fft(y,N);pyy=y.*conj(y);f=(0:(N/2-1));fori=1:N/2-1f(i)=f(i)*fs/N;endfigure(4)subplot(1,2,1),plot(f,pyy(1:N/2)),title('滤波前的波形频谱图像');y=fft(yy1,N);pyy=y.*conj(y);f=(0:(N/2-1));fori=1:N/2-1f(i)=f(i)*fs/N;endsubplot(1,2,2),plot(f,pyy(1:N/2)),title('滤波后的波形频谱图像')其中采样点为256个，采样频率为600Hz，输入信号为100Hz、250Hz、270Hz的合成信号，设定的截止频率为200Hz，通过FIR滤波器后，期望保留的信号是100Hz的信号，200Hz以上的频率基本被滤掉。图1是滤波前的图形，图2是滤波后的图形，图3为滤波器频谱图像，图4滤波前后的波形频谱图像。从这四个图中可以看住原始信号中的频率有100Hz、250Hz、270Hz，经过滤波后200Hz以上的信号成分基本上被滤掉。只留下100Hz的信号。图1滤波前波形图像图2滤波后波形图像图3滤波器的频谱图像图4.滤波前后的波形频谱图像在CCS环境的仿真首先配置处理器项，进入CCStudiov3.3中，编写程序，程序如下： .mmregs.reffilter_start.def_c_int00K_DATA_SIZE.set256K_BUFFER_SIZE.set32K_STACK_SIZE.set256K_B.set27K_CIR.setK_BUFFER_SIZESTACK.usect"stack",K_STACK_SIZESYSTEM_STACK.setK_STACK_SIZE+STACKDATA_DP.usect"filter_vars",0filterdata.usect"filter_vars",K_DATA_SIZEbufferdatay.usect"filter_vars",K_BUFFER_SIZE*2bufferdatax.usect"filter_vars",K_BUFFER_SIZE*2.data.globalinputdatainputdata.WORD16750,-5878,18090,-26831,6340,-9511,11750,11443.WORD-6910,0,-16750,5878,5570,9511,0,-7810.WORD-11750,5878,570,17321,-6910,-5878,-5570,-9511.WORD23660,-9511,18090,-23198,-570,0,570,23198,-18090.WORD9511,-23660,9511,5570,5878,6910,-17321,-570.WORD-5878,11750,7810,0,-9511,-5570,-5878,16750.WORD0,6910,-11443,-11750,9511,-6340,26831,-18090.WORD5878,-16750,0,16750,-5878,18090,-26831,6340.WORD-9511,11750,11443,-6910,0,-16750,5878,5570.WORD9511,0,-7810,-11750,5878,570,17321,-6910.WORD-5878,-5570,-9511,23660,-9511,18090,-23198,-570.WORD0,570,23198,-18090,9511,-23660,9511,5570.WORD5878,6910,-17321,-570,-5878,11750,7810,0.WORD-9511,-5570,-5878,16750,0,6910,-11443,-11750.WORD9511,-6340,26831,-18090,5878,-16750,0,16750.WORD-5878,18090,-26831,6340,-9511,11750,11443,-6910.WORD0,-16750,5878,5570,9511,0,-7810,-11750.WORD5878,570,17321,-6910,-5878,-5570,-9511,23660.WORD-9511,18090,-23198,-570,0,570,23198,-18090.WORD9511,-23660,9511,5570,5878,6910,-17321,-570.WORD-5878,11750,7810,0,-9511,-5570,-5878,16750.WORD0,6910,-11443,-11750,9511,-6340,26831,-18090.WORD5878,-16750,0,16750,-5878,18090,-26831,6340.WORD-9511,11750,11443,-6910,0,-16750,5878,5570.WORD9511,0,-7810,-11750,5878,570,17321,-6910.WORD-5878,-5570,-9511,23660,-9511,18090,-23198,-570.WORD0,570,23198,-18090,9511,-23660,9511,5570.WORD5878,6910,-17321,-570,-5878,11750,7810,0.WORD-9511,-5570,-5878,16750,0,6910,-11443,-11750.WORD9511,-6340,26831,-18090,5878,-16750,0,16750.WORD-5878,18090,-26831,6340,-9511,11750,11443,-6910.WORD0,-16750,5878,5570,9511,0,-7810.text_c_int00:.asgAR2,ORIGIN.asgAR3,INPUT.asgAR4,FILTER.asgAR5,OUTPUTSTART:SSBXFRCTSSBXINTMLD#DATA_DP,DPSTM#STACK,SPCALLfilter_startNOPNOPNOPLOOPBLOOP.defh0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11,h12,h13,h14,h15,h16,h17,h18,h19,h20,h21,h22,h23,h24,h25,h26.deffilter_starth0 .set0000Hh1 .set-003FHh2 .set008AHh3 .set0000Hh4 .set-015BHh5 .set01F0Hh6 .set0000Hh7 .set-03CDHh8 .set056EHh9 .set0000Hh10 .set-0D92Hh11 .set1DDBHh12 .set4F2AHh13 .set2349Hh14 .set-1049Hh15 .set0000Hh16 .set06C9Hh17 .set-04E3Hh18 .set0000Hh19 .set02B7Hh20 .set-0209Hh21 .set0000Hh22 .set0116Hh23 .set-00BEHh24 .set0000Hh25 .set0035Hh26 .set0000H.textfilter_start:STM#K_CIR,BKSTM#1,AR0 ；设置循环缓冲区的大小和步长STM#inputdata,ORIGINSTM#bufferdatax,INPUT;STM#bufferdatay,FILTERSTM#filterdata,OUTPUT STM#K_DATA_SIZE-1,BRC ；设置快循环计数器RPTBfilter_end-1MVDD*ORIGIN+,*INPUTRPT#K_B-1-1MAR*INPUT-0%MPY *INPUT+0%,#h26,B LD B,A MPY *INPUT+0%,#h25,B ADD B,A MPY *INPUT+0%,#h24,B ADD B,A MPY *INPUT+0%,#h23,B ADD B,A MPY *INPUT+0%,#h22,B ADD B,A MPY *INPUT+0%,#h21,B ADD B,A MPY *INPUT+0%,#h20,B ADD B,A MPY *INPUT+0%,#h19,B ADD B,A MPY *INPUT+0%,#h18,B ADD B,A MPY *INPUT+0%,#h17,B ADD B,A MPY *INPUT+0%,#h16,B ADD B,A MPY *INPUT+0%,#h15,B ADD B,A MPY *INPUT+0%,#h14,B ADD B,A MPY *INPUT+0%,#h13,B ADD B,A MPY *INPUT+0%,#h12,B ADD B,A MPY *INPUT+0%,#h11,B ADD B,A MPY *INPUT+0%,#h10,B ADD B,A MPY *INPUT+0%,#h9,B ADD B,A MPY *INPUT+0%,#h8,B ADD B,A MPY *