TCrossSpectrumAnalyzer Class

Summary

Performs cross spectrum analysis.

Hierarchy
TAnalysis <--TSpectrum <--TStaticSpectrumAnalyzer <--TCustomSpectrumAnalyzer <--TSpectrumAnalyzer <--TCrossSpectrumAnalyzer

Subclasses
None

Description

Cross spectrum analysis is used most to determine transfer function of the system, determine the presence of non-linearities in the analyzed system with the coherence and determine frequency spectrums of Input and Output. The coherence is defined as:


                  |E( X * conj(Y) )|
     coherence = ---------------------
                   |E(X)| * |E(Y)|

Transfer function is defined as:


            E(|Y|)
     tf = ---------
            E(|X|)

where X is the complex frequency spectrum of the signal entering the system and Y is the complex frequency spectrum of the signal exiting the system.

The component features two modes of operation: Recursive and non-recursive. In Recursive mode (Recursive property = True), all the spectral parameters are update for every call to the Update method. This mode can be used to run cross spectral analysis on-line in real time, if you enable infinite exponential averaging. In Non-recursive mode (Recursive property = false), only averaging is performed when calls are made to the Update method. Once the averaging has finished, CrossAnalyzer.Update method must be called to calculate the actual spectra and a call to UpdateSpectrum will place the correct spectrum in the Amplt/Phase property. This approach is more CPU efficient then the first. Because cross spectral analysis is based on averaging, you can not change the parameters of the frequency spectrum of already averaged data.

Properties

Name	Summary
ComplexSpectrum
CrossAnalyzer
OnUpdateSpectrum
Output

Methods

Name	Summary
BrowseCrossSpectrum
InternalUpdate
Update
UpdateSpectrum

Events

Name	Summary
OnGetInputSpectrum
OnGetoutputSpectrum