Hi Dora,
OK. I guessed that it could be simulation results, but i got confused by the mention of a DAQ board.
I think that it is possible to expand the chirp bandwidth beyond the band of interest, in such a way that this whole band is far inough from the edges of the chirp.
There is another degree of freedom for the chirp control: the sweeping speed. It is possible to make a nonlinear frequency sweep, controlling in this way the autocorrelation function and the spectral contents. For instance, nonlinear frequency sweep (with a slower sweep at the start and the end) could compensate the decrease at the band edges due to windowing (amplitude shaping).
Nevertheless, thinking in Woodward’s theorem, I’m not sure that this can produce a big improvement. In any case, an increase in the product duration*bandwidth reduces the errors and increase the dynamic range.
Regards
Z