estimate frequency respond using random or chirp signal

Hi everyone,

i'm trying to estimate the frequency respond of this system. It can easily be done with Sinestream but it took too much time cause i want frequecy range from 0.1 to 1000. With random signal i get different result and with chirp i get into this error. My question is, which setting should i use with random or chirp signal to precisely estimate this system? Thanks all.