7.09 coherence. Number calculated from the cross spectrum, ranging from 0 to 1 indicating to what degree the output of a system is linear, causal, and time invariant, with respect to the input.
Annotation 1 The coherence, γ2, is calculated as
where GAB is the cross spectrum, GAA is the input auto spectrum, and GBB is the output auto spectrum.
Annotation 2 Coherence also may be reduced by additive noise at the system input or output.« Back to Standards Terminolgy Index