%画图~以f为横坐标，功率谱值为纵坐标，但是把相应位置的f改成对应周期，f本身画到上面的横坐标去 position = [0.1 0.15 0.8 0.3]; %  plot(east_ciso_f, east_ciso_S ,LineWidth=2) % 连续功率谱 ylim([-0.01 0.1]);%xlim([1/365 0.5]) hold on; plot(east_ciso_f, sw, 'r--',LineWidth=2) % 检验线 %set second xtick~~~ xticks([0 1/30 1/15 0.1 0.2 0.3 0.5]);%想显示的值标出来 f = xticks; xticklabels(sprintfc('%.0f',1./f));%精度保留0位小数~f换成倒数就是周期啦~ set(gca,'xaxislocation','bottom','position',position); xlabel('period (days)') %x of f on the top: axes; plot(east_ciso_f,east_ciso_S,LineWidth=2 ) % 连续功率谱 hold on; plot(east_ciso_f, sw, 'r--',LineWidth=2) % 检验线 set(gca,'xaxislocation','top','position',position); ylim([-0.01 0.1])% xlim([2 30]); legend('功率谱S','红噪声谱Sw') xlabel('频率f') ;ylabel('power spectrum') ; %  % line of time subplot("Position",[0.1 0.6 0.8 0.3]) plot(x,east_ciso,LineWidth=2)  xlim([x(1) x(365)]) %去掉了两头留白 datetick('x','mm','keeplimits') %datetick('x','mm','keepticks')%这比上一条指令在末尾多了个1 hold on p=refline([0 mean(east_ciso)]); %参考线 set(p,"Color",'green','LineWidth',2) title('东区多年平均时间序列');