public class TSignalDecimator : TSignalMultiRate
Performs signal decimation.
Signal decimation component. Use this component to lower the sampling frequency of the signal by powers of two using fast multi-rate, multi-stage filters (See [1]). The component also features a high quality envelope detection, which computes the absolute value of the source signal before the decimation. Decimation factors can be as high as 1024 or 4096. This makes it possible to detect very low frequencies with the envelope detector. The CPU load increases by only about twice when the decimation
factor is increased from 2 to any number (can be 1024).
References:
[[1] Understanding digital signal processing., Richard G. Lyons, Prentice-Hall, 2001.]([1] Understanding digital signal processing., Richard G. Lyons, Prentice-Hall, 2001.)
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. |
| AudioSignal | Boolean | Adjust filters for audio signal. |
| 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. |
| EnvelopeFactor | Int32 | Defines the filter stage at which to apply envelope detection. |
| ExternalTaps | Boolean | Enables user specified filter. |
| Factor | Int32 | Decimation/Interpolation factor. |
| FilterDelay | Double | Returns the filter delay in number of samples of the final sampling frequency. |
| 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. |
| HalfBand | Boolean | Filters out upper half of the bandwidth. |
| HzRes | Double | Frequency resolution obtained, if an FFT algorithm would be run on the data. |
| Initialized | Boolean | When set to false, the next call to the update method will reinitialize the FIR filters. |
| 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. |
| LastStageFilterOnly | Boolean | The component lowers the sampling frequency in steps by a factor of two. |
| 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. |
| OnGetFilterTaps | TNotifyEvent | Triggered when ExternalTaps is false. |
| 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. |
| Ripple | Double | Maximum ripple allowed in the passband and in the stopband. |
| SamplingFrequency | Double | Defines the sampling frequency of the signal. |
| SamplingTime | Double | The length of the signal in seconds. |
| ScaleFactor | Double | Defines the factor by which the signal will be scaled. |
| SuspendNotifyUpdate | Boolean | Set this property to True, to prevent calling OnNotifyUpdate from the Update Method. |
| TransBW | Double | Defines the width of the transition band of the FIR filter used for interpolation/decimation. |
| 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. |
| InitFilters | FirTaps and FinalStageTaps do not hold valid filter taps until InitFilters has been called. |
| 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. |
| 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. |
| Process | Filter Src and place the result in Dst. |
| Pull | Request recalculation of the entire chain of all connected components. |
| PullUntilEnd | Calls Pull until pipeEnd is returned. |
| Reset | The same as setting Initialized to false. |
| 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. |
| OnGetFilterTapsEvent | Triggered when ExternalTaps is false. |
| 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". |