TSpectrumAnalyzer Class

type TSpectrumAnalyzer = class(TCustomSpectrumAnalyzer);

Computes and analyzes a frequency spectrum.

Estimates the single-sided amplitude and phase spectrum of the signal on the Input property and stores the result in Self.Amplt and Self.Phase. For a real sinusoid of amplitude A that falls exactly on FFT bin k (with a rectangular Window and ZeroPadding = 1, i.e. $0 < k < N/2$ ) the amplitude spectrum reads back the true amplitude, Amplt[k] = A, f_k = k * HzRes, HzRes = F_s/N. The complex DFT X[k]=sum_(n=0)^(N-1) x[n] e^(-j 2pi k n / N) is scaled so that, away from DC and Nyquist, Amplt[k] = (2 | X[k]|)/(N CG), CG = 1/Nsum_(n=0)^(N-1) w[n], where w is the chosen Window and CG its coherent gain, so the recovered amplitude is independent of the window. SpectrumType selects the readout: power =Amplt^2, RMS =sqrt(2)/2 Amplt, peak-peak =2 Amplt. Parseval holds: the mean square of the time signal equals 1/2sum_(k>0)Amplt[k]^2 plus the DC term. Method chooses FFT, an autoregressive estimator (Yule-Walker, Burg, covariance, modified covariance) of order ArOrder, or the chirp-Z transform; the AR estimators recover spectral resonances of an AR process. DCDump removes the mean before the transform; an empty Input yields an empty spectrum. The resulting spectrum is always placed in Self.Amplt (amplitude spectrum) and Self.Phase (phase spectrum).

Properties

Name	Type	Description
Active	Boolean	Set active to false to suppress the propagation of the Pull request and the subsequent call to the Update method.
ActualZeroPadding	Double	Ready only. Returns the ratio between the original signal length and the length of the analyzed signal padded with zeros.
Amplt	TVec	Stores the amplitude of the spectrum.
ArOrder	Integer	Defines the order for the autogressive spectral estimators.
Averages	Integer	Used to store the number of averages made.
Bands	TSpectrumBandsAnalyzer	Holds the parameters for the frequency bands.
BandWidth	Double	Returns the bandwidth of the spectrum in [Hz].
BandwidthH	Double	Returns the upper bandwidth edge of the signal.
BandwidthL	Double	Returns the lower bandwidth edge of the signal.
BlockAssign	Boolean	Block streaming of specific properties when storing only a "template".
Complex	Boolean	Set this property to true, to request computation using complex numbers.
ComplexSpectrum	TVec	After the first call to Update method, this property returns a pointer to the scaled complex spectrum.
ConjExtend	Boolean	If True, the conjugate symmetric part of the frequency spectrum is to be computed.
ConjFlip	Boolean	If True, the conjugate symmetric part of the frequency spectrum will be placed in 0.5..1.0 Fs (as returned by the FFT), and not between -0.5..0.0 Fs.
Continuous	Boolean	If True, the component will pass on the udpate request to the connected component.
CrossSpectral	Boolean	If True, calculate the cross spectrum and not the transfer function.
CZT	TSpectrumCZT	Holds Chirp Z-transform configuration.
DCDump	Boolean	If True, the DC component will be removed from the signal prior to the transform to the frequency domain.
Dt	Double	Returns the distance in seconds between two consecutive samples of the signal on which the frequency spectrum is based.
EditorActive	Boolean	Returns True, if the component editor is displayed.
ExpWindow	Double	The parameter for the exponential windowing function.
FloatPrecision	TMtxFloatPrecision	Set this property to request computation in 32bit/64bit precision with real/complex numbers.
FloatPrecisionLock	Boolean	Set this property to true to lock changes to FloatPrecision property.
Harmonics	Integer	Defines number of harmonics to be used when calculating statistical parameters from the amplitude spectrum.
HzRes	Double	Returns the frequency resolution in Hz.
Input	TAnalysis	Connector property to obtain a pointer to the TSignal component holding the data to be processed.
Integration	TIntegration	Define the integration/differenation of the frequency spectrum.
IsDouble	Boolean	Set this property to false, to request computation in 32bit floating point precision, 64bit, if true.
IsSpectrumAnalyzer	Boolean	Returns true, if the descendant class is derived from TSpectrumAnalyzer.
ItemNumber	Integer	Number to label the object when it is an item in the List.
Length	Integer	Defines the length of the spectrum.
Logarithmic	Boolean	Set it to True, to obtain the logarithm of the spectrum in dB.
LogBase	Double	Defines the base of the logarithmic spectrum.
LogScale	Double	Defines the scaling of the logarithmic spectrum.
LogSpan	TLogSpan	Defines the span of the logarithmic spectrum in dB.
LogType	TLogType	Specify how to apply the logarithm to the spectrum.
MainlobeWidth	Integer	Defines the width of the main lobe. Each frequency component in the frequency spectrum should theoretically be infinitely thin.
Marks	TMarkList	Stores the frequency, amplitude and phase of selected frequency bins.
MaxAmplt	Double	Stores the maximum value of the Amplt spectrum found by the MinMaxAmplt method.
MaxFreqIndex	Integer	Holds the index at which the maximum amplitude was found by the MinMaxAmplt method.
MaxPhase	Double	Stores the maximum value of the Phase spectrum found by the MinMaxPhase method.
Method	TSpectrumMethod	Defines the method to be used for frequency spectrum estimation.
MinAmplt	Double	Stores the minimum value of the Amplt spectrum found by the MinMaxAmplt method.
MinPhase	Double	Stores the minimum value of the Phase spectrum found by the MinMaxPhase method.
OnAfterAverage	TNotifyEvent	Event triggered just after the average has been applied.
OnAfterComplexSpectrum	TNotifyEvent	Event triggered just after complex spectrum has been computed, but before averaging in the complex domain.
OnAfterUpdate	TNotifyEvent	The event is triggered after the call to the Update method.
OnBandsUpdate	TNotifyEvent	If assigned, this event will be called instead of a call to Bands.Update method.
OnBeforeAverage	TNotifyEvent	Event triggered just before the average is applied.
OnBeforeSpectrumType	TNotifyEvent	Event triggered just before spectrum type is aplied, but after averaging in the complex domain.
OnBeforeUpdate	TNotifyEvent	The event is triggered just before the call to the Update method.
OnDisplayUpdate	TNotifyEvent	The event is triggered after the OnAfterUpdate event. Use this event to update any associated charts or graphs or result tables.
OnGetInput	TNotifyEvent	If the Input property is not assigned, the component will call OnGetInput.
OnNotifyUpdate	TNotifyEvent	The event is called after a call to InternalUpdate, OnAfterUpdate and OnDisplayUpdate from within the Update method.
OnParameterUpdate	TNotifyEvent	The event is triggered when ParamUpdate method is called. The ParamUpdate method is usually called by component editors when a value was changed by the user and the editor was "Live".
OnPeaksUpdate	TNotifyEvent	If assigned, this event will be called instead of a call to Peaks.Update method.
Peaks	TSpectrumPeaksAnalyzer	Pointer to the component that manages peak analysis.
Phase	TVec	Stores the phase of the spectrum.
PhaseMode	TPhaseMode	This property determines how to handle the phase of the frequency spectrum.
PhaseRange	TPhaseRange	Specify the range of the phase spectrum.
PhaseUnits	TPhaseUnits	Defines the units of phase. (radian, degrees).
PipeState	TPipeState	Returns the state of the pipe after the last update.
Reference	TReferenceList	Stores a list of components that have to be notified, when this component is destroyed.
Report	TSpectrumReport	Holds the parameters needed to generate a spectrum analysis report. Requires that the descriptor property is properly filled up.
Rotation	Integer	Before the frequency analysis, the signal can be circularly rotated by a specified number of samples. Rotation defines the number of samples.
RunningPhase	TRunningPhase	Defines how to remove the constant (running) phase from the phase spectrum.
SamplingFrequency	Double	Defines the sampling frequency of the signal on which the frequency spectrum is based.
SamplingTime	Double	Defines the length of the signal on which the frequency spectrum is based in seconds.
ScaleFactor	Double	Frequency spectrum will be scaled by a scale factor.
SidelobeAtt	Double	Specifies the attenuation of the main sidelobe in dB. This parameter applies only, if you use the Kaiser or Chebyshev window.
SpectrumScale	Double	The scaling factor applied to the frequency spectrum.
SpectrumType	TSpectrumType	Specifies the spectrum type to be computed.
Stats	TSpectrumStats	Defines the parameters for the averaging and statistical analysis.
SuspendNotifyUpdate	Boolean	Set this property to True, to prevent calling OnNotifyUpdate from the Update Method.
UnwrapPhase	Boolean	If True, the phase of the phase spectrum will be "unwrapped".
UsesInputs	Boolean	Set it to True to indicate, that valid signals will be connected to the Input or Inputs properties.
Window	TSignalWindowType	Specifies the window type to be used. Windows decrease spectral leakage, but also decrease spectral resolution.
ZeroPadding	Integer	Defines the level of zero padding of the source signal.

Methods

Name	Description
Add	Add amplitude and phase of the ASpectrum to the current spectrum.
AllowStreaming	Returns the negatated value of BlockAssign.
AmpltEst (4)	Returns the phases of the amplitudes at Freq frequencies according to the value of the Peaks property.
AmpltLogEst (2)	Converts the amplitude of the frequency spectrum at Freq frequency to dB according to the value of the Peaks property.
AmpltSpectrum	Compute amplitude spectrum from X.
Assign	Assign values of all published properties from Source.
AssignTemplate	Assign values of "template-like" published properties from Source.
BandFlip	Flip the frequency spectrum on the frequency axis.
ComplexEst (3)	Returns the complex value of the Freq frequencies according to the value of the Peaks property.
ComputeSpectrum	Compute the frequency spectrum where the Num is the numerator and Den is the denominator of the transfer function.
ConvergeToMaximum (2)	Searches for the closest peaks of the amplitude spectrum.
Copy	Copy ASpectrum to the calling spectrum.
Differentiate	Differentiate the underlying signal in the frequency domain by scaling each amplitude line with a power of its angular frequency.
Divide	Divide the calling the spectrum with ASpectrum.
EditorClass	To be overriden in descendanr classses.
FilterPeak	Filter the peak defined with a TMarkRecord record stored at position Index within Marks list from Input.Data.
FreqToFreqIndex	Computes range checked array indexes in the spectrum from frequency values.
InputsDirty	If all Inputs[i] are dirty the function returns true.
Integrate	Integrate the underlying signal in the frequency domain by dividing each amplitude line by a power of its angular frequency, restoring the DC term afterwards.
InternalPull	When called, the method will pass Update requests recursively to all connected objects.
Invalidate	Notifies all connected components that this component has fresh data.
LoadFromStream	Load the component from Src stream.
LoadTemplateFromFile	Load a template from file.
LoadTemplateFromStream	Load a template from stream.
LogAmplt	Compute the logarithm of the amplitude spectrum and convert to dB.
MarksToStrings	Convert marks to strings.
MinMax	Calls MinMaxAmplt and MinMaxPhase.
MinMaxAmplt	Find minimum and maximum value of the Amplt spectrum.
MinMaxPhase	Find minimum and maximum value of the Phase spectrum.
Mul	Multiply the calling the spectrum with ASpectrum.
NF	Noise floor in dB: the mean absolute noise line (lines outside the mark guard bands), relative to the largest marked peak.
ParamUpdate	The method can be assigned to some other component even handler, as a notification that a parameter has changed and that Self should consider a recalculation.
PeakApproximate (2)	Find the peak nearest to the Freq frequency and return the frequenyc of the newly found peak.
PhaseEst (4)	Returns the phase of the frequency spectrum at Freq frequency according to the parameters of the Peaks property.
PhaseSpectrum	Compute phase spectrum from X.
PipeReset	Recursively processes all connected components backward and calls Reset method.
PowerSpectrum	Compute power spectrum from X.
Process	Compute the frequency spectrum where the SrcNum is the numerator and SrcDen is the denominator of the transfer function.
Pull	Request recalculation of the entire chain of all connected components.
PullUntilEnd	Calls Pull until pipeEnd is returned.
Reset	Reset is called after loading the data from stream or file.
ResetAveraging	Reset the frequency spectrum averaging.
RMS	Root-mean-square value reconstructed from the amplitude spectrum.
RMSSpectrum	Compute RMS spectrum from X.
SaveTemplateToFile	Save template to file.
SaveTemplateToStream	Save template to stream.
SaveToStream	Save the component to Dst stream.
Scale	Scale the calling spectrum with Factor.
SetZero	Initialize spectrum to zero.
SFDR	Spurious-free dynamic range in dB: the ratio of the largest marked peak to the second-largest marked peak.
SINAD	Signal-to-noise-and-distortion ratio in dB. Compares the largest marked peak against the noise floor plus every other marked peak.
Size	Assign Length, Complex and SamplingFrequency properties.
SNR	Signal-to-noise ratio in dB. Sums the absolute amplitudes of all marked peaks and compares against the sum of the absolute amplitude lines outside the mark guard bands.
Spectrum	Compute the spectrum from Input.Data according to the state of the component and place the result in Dst.
Sqr	Square the Amplt and Phase of the ASpectrum and copy it to self.
Subtract	Subtract ASpectrum from the calling spectrum.
THD	Total harmonic distortion in percent. Returns the RMS of the marked harmonic peaks (all marks after the first, when sorted by frequency, up to Harmonics) relative to the first (fundamental) marked peak.
THDN	Total harmonic distortion plus noise, in percent. Combines the noise floor power with the power of every marked peak except the largest, relative to the largest marked peak.
Update	Request recalculation of the data and place the result in Self.
UpdateLogarithmic	Call the method after changing the Logarithmic property.
UpdateNotify	Call this method only, if SuspendNotifyUpdate is True.
UpdateSpectrumStats	If Stats.Recursive was False, calling this method will compute the averaged spectrum and associated statistics.
ValuesToStrings	Convert values to strings.