方法一 findpeaks 寻找峰值函数

利用 findpeaks 工具箱函数可以找原始波形中的波峰，但是当单周期里出现多个极值，时findpeaks的判断会将极值也算入。

原波形为250HZ的正弦波型，

pks = findpeaks(data)
[pks,locs] = findpeaks(data) ------pks 对应峰值，locs 对应峰值位数
[...] = findpeaks(data,'minpeakheight',mph)----mph 设定峰值的最小高度
[...] = findpeaks(data,'minpeakdistance',mpd)----mpd 设定两峰值间的最小间隔数

clc;clear all;close all;data=[105.03 99.18 84.965 72.445 68.994 77.265...      91.052 100.61 98.215 86.363 74.439 71.625...      80.061 92.18 97.823 91.483 80.241 73.616...      78.547 89.084 94.924 89.689 79.898 75.485...      81.544 89.485 90.578 83.712 77.401 80.18...      86.904 88.721 83.468 78.971 81.983 86.25...      85.224 80.901 80.808 84.488];
plot(1:length(data),data,'k');xlabel('时间');ylabel('幅度');title('信号');grid on;hold on;%针对信号，进行峰值查找Nums=7;%指定峰值个数[pmax,lmax]=findpeaks(data,'minpeakdistance',3,'NPEAKS',Nums);%查找最大值[pmin,lmin]=findpeaks(-data,'minpeakdistance',3,'NPEAKS',Nums);%查找最小值%用红色标注最大值，绿色标注最小值scatter(lmax,pmax,'r*');hold on;scatter(lmin,-pmin,'go');hold on;

方法二差分运算寻找峰值函数

clc; close all; clear;  % 节点信息  data=[105.03 99.18 84.965 72.445 68.994 77.265...      91.052 100.61 98.215 86.363 74.439 71.625...      80.061 92.18 97.823 91.483 80.241 73.616...      78.547 89.084 94.924 89.689 79.898 75.485...      81.544 89.485 90.578 83.712 77.401 80.18...      86.904 88.721 83.468 78.971 81.983 86.25...      85.224 80.901 80.808 84.488];  % 微分变号信息  c=findpeaks(data);  IndMin=find(diff(sign(diff(data)))>0)+1;   %获得局部最小值的位置  IndMax=find(diff(sign(diff(data)))<0)+1;   %获得局部最大值的位置  figure; hold on; box on;  plot(1:length(data),data);  plot(IndMin,data(IndMin),'r^')  plot(IndMax,data(IndMax),'k*')  legend('曲线','波谷点','波峰点')  title('计算离散节点的波峰波谷信息', 'FontWeight', 'Bold');