能不能帮忙解答一下这段代码,这段代码是提取excel表格中两列数据的,第一列是时间,第二列是速度
clear
clc
filename = 'Impulse_TimeSignal.xlsx';
name= {'Impulse_low','Impulse_high'};
for i = 1:2
% read data
sheet = i;
vel = xlsread(filename,sheet); % low frequency
t = vel(:,1);
dt = t(2)-t(1);
vel(:,[1 2]) = [];
acc = diff(vel)/dt;
% calculate acceleration
outAcc = zeros(size(vel));
outAcc(1) = 0; % initial value
for k = 2:length(t)
outAcc(k) = 2*acc(k-1)-outAcc(k-1);
end
% calculate vel, disp
outVel = cumtrapz(t, outAcc);
outDisp = cumtrapz(t, outVel);
% output
figure
plot(t(1:1000), outVel(1:1000))
hold on
plot(t(1:1000), vel(1:1000),'--')
Accl = [t,outAcc]';
fid = fopen([name{i},'.txt'], 'wt');
fprintf(fid, '%12.8f %12.8f\n', Accl);
fclose(fid);
end