MATLAB标记点

% clear

% clc

% close all

% % 生成随机时程信号

% fs=100;

% signalLength = fs*60*2;

% time = 1/fs:1/fs:signalLength/fs;

% randomSignal = 2*sin(2*pi*0.5*time)+3*cos(2*pi*1*time)+randn(1, signalLength);

function [frequencyPP]=funct_peak(signal,Hz)

% 生成随机时程信号

fs=Hz;

randomSignal=signal;

signalLength = length(randomSignal);

time = 1/fs:1/fs:signalLength/fs;

%功率谱密度图

pwel.window=1024*9;

pwel.noverlap=pwel.window/2

[pxx,f]=pwelch(randomSignal,pwel.window,pwel.noverlap,[],fs);

plot(f,10*log10(pxx))

xlim([0 2])

% 寻找峰值点

threshold = 20; % 定义阈值，即前后20个点的纵坐标差值的阈值

[pks, locs] = findpeaks(10*log10(pxx), 'MinPeakHeight', threshold);

% 标识峰值点

hold on

scatter(f(locs), pks, 'r', 'filled')

% 在每个峰值点的位置添加文本标签

for i = 1:length(locs)

text(f(locs(i)), pks(i), sprintf('%.2f', f(locs(i))), 'VerticalAlignment', 'bottom', 'HorizontalAlignment', 'center');

frequencyPP(i)=round(f(locs(i)),3);,

end

hold off