TSignalBrowseBuffer Class

public class TSignalBrowseBuffer : TSignal

Stores and buffers an overview of the incoming signal.

The size of the preview is maintained small enough to allow quick redraw on a chart. At start the component holds the actual signal up to the size of the SpanLimit. Once SpanLimit is exceeded an overview of the signal is computed and the original is discarded. From that point on, only the overview of the signal is kept. Once the overview exceeds the SpanLimit a new signal overview is computed from the existing overview and this procedure repeats in to infinity allowing virtually unlimited length of the overview. The component allow's limited zoom-in in to the overview, because intermediate results are discarded, but the data discarded will not exceed a factor of sqr(Increment). The default value for increment is 20 and 20^2 = 400. For a 2GB long recording this will result in 5MB of the in-memory buffer. On the resulting overview PixelDownSample method should be applied again. For true navigation use TSignalBrowse component.

The purpose of this component is to allow an overview of already recorded data to be displayed to the user. The IsOverview function returns true, if the component stores an overview, otherwise it is still buffering the original signal. This is important to know because the drawing method may differ substantially for signal and overview. The overview stores Max and Min values interleaved. The Max values form the upper and the Min values from the lower envelope.

Calling Update or Pull method will return pipeOK, if the Data property has been updated. It will return pipeStream, if there is not enough data buffered yet to update.

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.
BandWidth	Double	Return the bandwidth of the signal.
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".
ChannelCount	Int32	Get or set the number of channels multiplexed in the data property.
Complex	Boolean	Set this property to true, to request computation using complex numbers.
Continuous	Boolean	If True, the component will pass on the udpate request to the connected component.
Data	TVec	Stores the result of the processing.
Dt	Double	Time between two consecutive samples.
EditorActive	Boolean	Returns True, if the component editor is displayed.
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.
HzRes	Double	Frequency resolution obtained, if an FFT algorithm would be run on the data.
Increment	Int32	Defines the increment at which the overview is sampled.
Input	TAnalysis	Connector property to obtain a pointer to the TSignal component holding the data to be processed.
IsDouble	Boolean	Set this property to false, to request computation in 32bit floating point precision, 64bit, if true.
Item	Double	Default property to access values of a real signal.
ItemNumber	Int32	Number to label the object when it is an item in the List.
Length	Int32	Get or set the length of the signal in samples.
Marks	TMarkList	Stores the time stamps and amplitude of selected samples.
MaxAmplt	Double	Stores the maximum amplitude of the signal found by the MinMax method.
MaxX	Double	Use the MaxX property to store the time stamp (in seconds) of the right most sample.
MinAmplt	Double	Stores the minimum amplitude of the signal found by the MinMax method.
MinX	Double	Use the MinX property to store the time stamp of the left-most sample.
OnAfterUpdate	TNotifyEvent	The event is triggered after the call to the Update method.
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".
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.
SamplingFrequency	Double	Defines the sampling frequency of the signal.
SamplingTime	Double	The length of the signal in seconds.
SpanLimit	Int32	Defines the samples count at which an overview is computed.
SuspendNotifyUpdate	Boolean	Set this property to True, to prevent calling OnNotifyUpdate from the Update Method.
UsesInputs	Boolean	Set it to True to indicate, that valid signals will be connected to the Input or Inputs properties.

Methods

Name	Description
AllowStreaming	Returns the negatated value of BlockAssign.
Append	Appends Sample to the end of the signal.
Assign	Assign values of all published properties from Source.
AssignTemplate	Assign values of "template-like" published properties from Source.
Copy	Copies signal Data and sampling frequency information.
Crest	Compute the CREST parameter.
EditorClass	To be overriden in descendanr classses.
InputsDirty	If all Inputs[i] are dirty the function returns true.
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.
IsOverview	Defines, if the component already stores an overview.
LoadFromStream	Load the component from Src stream.
LoadTemplateFromFile	Load a template from file.
LoadTemplateFromStream	Load a template from stream.
MarksToStrings	Convert marks to strings.
MinMax	Find minimum and maximum amplitude and store the result in the MinAmplt and MaxAmplt properties.
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.
Peak	Find the maximum deviation of the signal from its mean value.
PipeReset	Recursively processes all connected components backward and calls Reset method.
Pull	Request recalculation of the entire chain of all connected components.
PullUntilEnd	Calls Pull until pipeEnd is returned.
Reset	Reset the buffering and overview.
SaveTemplateToFile	Save template to file.
SaveTemplateToStream	Save template to stream.
SaveToStream	Save the component to Dst stream.
Size	Assign the size of the signal from Src.
Update	Request recalculation of the data and place the result in Self.
UpdateNotify	Call this method only, if SuspendNotifyUpdate is True.
ValuesToStrings	Convert values to strings.

Events

Name	Description
OnAfterUpdateEvent	The event is triggered after the call to the Update method.
OnBeforeUpdateEvent	The event is triggered just before the call to the Update method.
OnDisplayUpdateEvent	The event is triggered after the OnAfterUpdate event. Use this event to update any associated charts or graphs or result tables.
OnGetInputEvent	If the Input property is not assigned, the component will call OnGetInput.
OnNotifyUpdateEvent	The event is called after a call to InternalUpdate, OnAfterUpdate and OnDisplayUpdate from within the Update method.
OnParameterUpdateEvent	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".