Teager-Kaiser能量算子是一种非线性算子，它能有效提取信号的瞬时能量，对信号瞬时变化具有良好的时间分辨率。Teager-Kaiser能量算子只需信号三个采样点，即可快速跟踪信号的幅值和角频率变化，计算实现简单、运算量小。
clc
clear all
close all
load emg4TKEO.mat %import data
%% Apply TKEO
emgfilt=emg; %initialize filtered signal
for i=2:length(emgfilt)-1 %do not consider first and last time points to avoid edge effects
emgfilt(i)=emg(i)^2-emg(i-1)*emg(i+1); %TKEO
end
%% Convert to zscore
time0=dsearchn(emgtime',0); %find timepoint 0
emgZ=(emg-mean(emg(1:time0)))/std(emg(1:time0)); %zscore of original emg signal
emgfiltZ=(emgfilt-mean(emgfilt(1:time0)))/std(emgfilt(1:time0)); %zscore of filtered emg signal
%% Plot
emgnorm=emg./max(emg); %normalize original emg signal
emgfiltnorm=emgfilt./max(emgfilt); %normalize filtered emg signal
subplot(211)
plot(emgtime,emgnorm,'k')
hold on
plot(emgtime,emgfiltnorm,'r')
legend('Original','Filtered')
title('EMG energy (TKEO)')
xlabel('Time (ms)')
ylabel('Amplitude')
subplot(212)
plot(emgtime,emgZ,'k') %plot zscore of original emg signal
hold on
plot(emgtime,emgfiltZ,'r') %plot zscore of filtered emg signal
legend('Original','Filtered')
title('Zscore of EMG')
xlabel('Time (ms)')
ylabel('Zscore')
区别于传统的信号能量定义，Teager-Kaiser 能量算子在考虑信号幅值效应的基础上，还考虑了信号瞬时频率的影响，是幅值的平方与瞬时频率平方的乘积，且与信号初始相位无关，可以很好地跟随信号的幅值及频率的变化，并在一定程度上可避免由于运动误差以及信号串扰造成的干扰，提高肌电信号信噪比。
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擅长领域：现代信号处理，机器学习，深度学习，数字孪生，时间序列分析，设备缺陷检测、设备异常检测、设备智能故障诊断
