ONOSOKKI DS-2000 series Operation Manual page 17

4-2 Checking Frequency Response Function Data under
Observation
Here, check data by displaying the frequency response function at the top and the
coherence function at the bottom.
* The coherence function represents the correlation between input and output signals.
Coherence becomes worse if noise is mixed between input and output or if rattling or
other nonlinear factor is present.
The higher the coherence, the higher becomes the reliability of the frequency response
function. The coherence is displayed as a level between 0 and 1 in the Y-axis range.
(The coherence function cannot be calculated without averaging.)
CAUTION:
1. The copyright of this procedure manual is reserved by Ono Sokki Co., Ltd.
2. Duplication without prior permission is prohibited.
3. This procedure manual explains general measurement procedures. Ono Sokki assumes no
responsibility for data obtained through a specific operation performed by the customer.
Coherence function
16
Frequency response function