MATLAB 轴心轨迹图、幅值谱、相位谱、功率谱(转)要点

1、MATLAB 编程，题目如下x=6*sin(60*pi*t+8*sin(120*pi*t+pi/6;y=8*sin(60*pi*t+pi/2+3*sin(120*pi*t+pi/4;程序一：两个波形图和轴心图clear;close all;sf=800;%采样频率;N=512;%采样点数t=0:1/sf:1;x=6*sin(60*pi*t+8*sin(120*pi*t+pi/6;y=8*sin(60*pi*t+pi/2+3*sin(120*pi*t+pi/4;subplot(2,1,1; %生成m*n个图，当前激活第一个图 plot(t,x;xlabel(时间t 单位s; % x轴注解ylab

2、el(幅值x 单位cm; % y轴注解title(A的波形图; % 图形标题grid on; % 显示格线subplot(2,1,2;plot(t, y, g;xlabel(时间t 单位s; % x轴注解ylabel(幅值y 单位cm ; % y轴注解title(B的波形图; % 图形标题grid on; % 显示格线%轴心轨迹图figure(2plot(x,y,bgrid on;程序二：计算X 、Y 的波形系数和波峰系数%x y的波形系数和波峰系数clc;close all;sf=800;t=0:1/sf:1;x=6*sin(60*pi*t+8*sin(120*pi*t+pi/6;xav=m

3、ean(abs(x;%平均绝对值xp=max(x;%幅值也就是最大值z=x.2;d=mean(z;xrms=sqrtm(d;%有效值Ft=xrms/xav;Fc=xp/xrms;disp(x的波形系数是;disp(num2str(Ft;disp(x的波峰系数是;disp(num2str(Fc;%y的波形系数和波峰系数y=8*sin(60*pi*t+pi/2+3*sin(120*pi*t+pi/4;x=y;xav=mean(abs(x;%平均绝对值xp=max(x;%幅值也就是最大值z=x.2;d=mean(z;xrms=sqrtm(d;%有效值Ft=xrms/xav;Fc=xp/xrms;di

4、sp(y的波形系数是;disp(num2str(Ft;disp(y的波峰系数是;disp(num2str(Fc;程序三：求解幅频谱、相频谱、功率谱%幅频谱、相频谱、功率谱clc;fs=800;%设定采样频率N=512;%采样点数n=0:N-1;t=n/fs;y=8*sin(60*pi*t+pi/2+3*sin(120*pi*t+pi/4;%进行FFT 变换并做幅频谱yy=fft(y,N;%进行fft 变换py1=yy/512;py2=py1*2;%单边谱乘以2mag= abs(py2 ;%求幅值f=(0:256*800/512;subplot(2,1,1;plot(f,mag(1:257;%做

5、幅频谱图xlabel(频率(Hz;ylabel(幅值;title(B的幅频谱;grid;%功率谱power=mag(1:257.2;subplot(2,1,2;plot(f,power;grid on;title(B的功率谱;xlabel(频率(Hz;ylabel(功率;%相频图pyy=angle(yy;Pyy=180/pi*pyy;%弧度变角度figure(2;plot(f,Pyy(1:257;gridon;title(B的相频谱;xlabel(频率(Hz;ylabel(相位（度）;程序四：%相关系数和相干性clc;closeall;dt=1/800;sf=800;t=0:1/800:1;x

6、=6*sin(60*pi*t+8*sin(120*pi*t+pi/6;y=8*sin(60*pi*t+pi/2+3*sin(120*pi*t+pi/4;%相关系数N=128;a=xcorr(x,y,128;a=a(N+1:2*N+1;plot(t(1:N,a(1:N;gridon;%求A 、B 的相干函数figure(2;N=512;cxy,w=cohere(x,y,N/4,sf,hamming(N/4,0,mean; plot(w,cxy;grid;title(相干分析;xlabel(频率(Hz;以下是matlab help的例子t = 0:0.001:0.6;x = sin(2*pi*50*t+sin(2*pi*120*t;y = x + 2*randn(size(t;plot(1000*t(1:50,y(1:50title(Signal Corrupted with Zero-Mean Random Noise xlabel(time (millisecondsY = fft(y,512;Pyy