全局波峰波谷：max();min();
所有波峰波谷：findpeaks();
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 

[...] = findpeaks(data,'threshold',th) 

[...] = findpeaks(data,'npeaks',np) 

[...] = findpeaks(data,'sortstr',str)