how to detect harmonic frequencies in simulink

Hello ,

right i am using multisine disturbance generator block . it generates multisine

like

sequence1 = [45;200;250]

sequence2 = [150;355;450]

to detect or dispaly frequencies i am using spectrum scope but it only displays first frequecies ... 45 and 150 its not displaying rest harmonics ...

the block model

multisine generator ----> zero order hold ----->spectrum scope

so any other way to dispaly harmonics in simulink ?