5 frf (hx) – Soft dB Opus Suite Data Logger Module User Manual
Page 38

37
9.1.5
FRF (Hx)
The FRF (Hx) module allows computing the average frequency response between channels. The
following figure presents the FRF module interface:
At any time, the computation parameters can be changed and the Recompute FRF button can be
used to update the results.
The FRF interface has two graphs: 1) The FRF graph to present the amplitude (or the phase) versus
the frequency, and 2) the coherence graph. Three types of FRF can be computed:
H1 using this equation:
H1=y/x=Sxy/Sxx
H2 using this equation:
H2=y/x=Syy/Sxy