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Difference between revisions of "NVGate FFT"
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→Correlation
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=====Correlation===== | =====Correlation===== | ||
Calculation of the Auto Correlation and the Cross Correlation. | Calculation of the Auto Correlation and the Cross Correlation. | ||
[[File:Correlation2.png|left]]<br> | |||
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* '''Correlation: '''Allows to activate or not the calculation of the correlation. | * '''Correlation: '''Allows to activate or not the calculation of the correlation. | ||
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* Use input '''AC '''coupling. Both auto correlation and cross correlation are disturbed by DC offset in the input signal. | * Use input '''AC '''coupling. Both auto correlation and cross correlation are disturbed by DC offset in the input signal. | ||
* Use appropriate trigger mode and trigger delay. The trigger mode should be different from free run. The trigger Delay must be set to –T/2 (where T is the time signal block length) with the Uniform and Centered Zero Padding correlation weighted window (and 0 for the Left Zero Padding window). But in some cases, especially with the Centered Zero Padding and Left Zero Padding window (as these function types attenuate parts of the trigger signal block), the trigger Delay must be adjusted to position the input signal with respect to time. | * Use appropriate trigger mode and trigger delay. The trigger mode should be different from free run. The trigger Delay must be set to –T/2 (where T is the time signal block length) with the Uniform and Centered Zero Padding correlation weighted window (and 0 for the Left Zero Padding window). But in some cases, especially with the Centered Zero Padding and Left Zero Padding window (as these function types attenuate parts of the trigger signal block), the trigger Delay must be adjusted to position the input signal with respect to time. | ||
=====Overall analysis===== | =====Overall analysis===== | ||
Calculation of the FFT bands sum. | Calculation of the FFT bands sum. | ||