FVTool

Filter Visualization Tool

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描述

Filter Visualization Toolis an interactive tool that enables you to display the magnitude, phase response, group delay, impulse response, step response, pole-zero plot, and coefficients of a filter. You can export the displayed response to a file withFile>Export.

If the DSP System Toolbox™ product is installed,FVToolcan also visualize the frequency response of a filter System object™. If you need to filter streaming data in real time, using System objects is the recommended approach. For more information, seefvtool.

Open the FVTool

TheFVToolcan be opened programmatically using one of the methods described inProgrammatic Use.

Examples

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Magnitude Response of Elliptic Filter

Open Live Script

Display the magnitude response of a 6th-order elliptic filter. Specify a passband ripple of 3 dB, a stopband attenuation of 50 dB, a sample rate of 1 kHz, and a normalized passband edge of 300 Hz. Start FVTool from the command line.

[b,a] = ellip(6,3,50,300/500); fvtool(b,a)

Display Analysis Parameters

Open Live Script

Display and analyze multiple FIR filters, starting FVTool from the command line.

b1 = firpm(20,[0 0.4 0.5 1],[1 1 0 0]); b2 = firpm(40,[0 0.4 0.5 1],[1 1 0 0]); fvtool(b1,1,b2,1)

Display the associated analysis parameters by selectingAnalysis > Analysis Parameters.

FVTool Figure Handle Commands

Open Live Script

Start FVTool from the command line. Display the magnitude response of a 6th-order elliptic filter. Specify a passband ripple of 3 dB, a stopband attenuation of 50 dB, a sample rate of 1 kHz, and a normalized passband edge of 300 Hz.

[b,a] = ellip(6,3,50,300/500); h = fvtool(b,a)

h = Figure (filtervisualizationtool) with properties: Number: 1 Name: 'Filter Visualization Tool - Magnitude Response (dB)' Color: [0.9400 0.9400 0.9400] Position: [346.5000 282.5000 583 437] Units: 'pixels' Use get to show all properties

Display the phase response of the filter.

h.Analysis ='phase'

h = Figure (filtervisualizationtool) with properties: Number: 1 Name: 'Filter Visualization Tool - Phase Response' Color: [0.9400 0.9400 0.9400] Position: [346.5000 282.5000 583 437] Units: 'pixels' Use get to show all properties

Turn on the plot legend and add text.

legend(h,'Phase plot')

Specify a sample rate of 1 kHz. Display the two-sided centered response.

h.Fs = 1000; h.FrequencyRange='[-Fs/2, Fs/2)'

h = Figure (filtervisualizationtool) with properties: Number: 1 Name: 'Filter Visualization Tool - Phase Response' Color: [0.9400 0.9400 0.9400] Position: [346.5000 282.5000 583 437] Units: 'pixels' Use get to show all properties

View the all the properties of the plot. The properties specific to FVTool are at the end of the list.

get(h)

网格:‘上’传说:‘上’AnalysisToolbar:”“FigureToolbar: 'on' DesignMask: 'off' SOSViewSettings: [1x1 dspopts.sosview] Fs: 1000 Alphamap: [1x64 double] CloseRequestFcn: 'closereq' Color: [0.9400 0.9400 0.9400] Colormap: [256x3 double] CurrentAxes: [1x1 Axes] CurrentCharacter: '' CurrentObject: [0x0 GraphicsPlaceholder] CurrentPoint: [0 0] DockControls: 'on' FileName: '' IntegerHandle: 'on' InvertHardcopy: 'on' KeyPressFcn: '' KeyReleaseFcn: '' MenuBar: 'none' Name: 'Filter Visualization Tool - Phase Response' NextPlot: 'new' NumberTitle: 'on' PaperUnits: 'inches' PaperOrientation: 'portrait' PaperPosition: [1.3350 3.3150 5.8300 4.3700] PaperPositionMode: 'auto' PaperSize: [8.5000 11] PaperType: 'usletter' Pointer: 'arrow' PointerShapeCData: [16x16 double] PointerShapeHotSpot: [1 1] Position: [346.5000 282.5000 583 437] Renderer: 'opengl' RendererMode: 'auto' Resize: 'on' ResizeFcn: '' SelectionType: 'normal' ToolBar: 'auto' Type: 'figure' Units: 'pixels' WindowButtonDownFcn: '' WindowButtonMotionFcn: '' WindowButtonUpFcn: '' WindowKeyPressFcn: '' WindowKeyReleaseFcn: '' WindowScrollWheelFcn: '' WindowStyle: 'normal' BeingDeleted: 'off' ButtonDownFcn: '' Children: [15x1 Graphics] Clipping: 'on' CreateFcn: '' DeleteFcn: '' BusyAction: 'queue' HandleVisibility: 'on' HitTest: 'on' Interruptible: 'on' Parent: [1x1 Root] Selected: 'off' SelectionHighlight: 'on' Tag: 'filtervisualizationtool' UIContextMenu: [0x0 GraphicsPlaceholder] UserData: [] Visible: 'on' NormalizedFrequency: 'off' PhaseDisplay: 'Phase' NumberofPoints: 8192 PhaseUnits: 'Radians' FrequencyRange: '[-Fs/2, Fs/2)' OverlayedAnalysis: '' Analysis: 'phase' FrequencyVector: [1x256 double] PolyphaseView: 'off' ShowReference: 'on' FrequencyScale: 'Linear'

Magnitude and Phase Response of Bandpass FIR Filter

Open Live Script

Design a 50th-order bandpass FIR filter with stopband frequencies 150 Hz and 350 Hz and passband frequencies 200 Hz and 300 Hz. The sample rate is 1000 Hz. Visualize the magnitude and phase response of the filter.

N = 50; Fstop1 = 150; Fstop2 = 350; Fpass1 = 200; Fpass2 = 300; Fs = 1e3; bpFilt = designfilt('bandpassfir','FilterOrder',N,...'StopbandFrequency1',Fstop1,...'StopbandFrequency2',Fstop2,...'PassbandFrequency1',Fpass1,...'PassbandFrequency2',Fpass2,...'SampleRate',Fs); fvtool(bpFilt,'Analysis','freq')

Related Examples

Filter Analysis using FVTool

Programmatic Use

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`fvtool(b,a)`

fvtool(b,a)opens FVTool and displays the magnitude response of the digital filter defined with numeratorband denominatora.

`fvtool(sos)`

fvtool(sos)opens FVTool and displays the magnitude response of the digital filter defined by theL-by-6 matrix of second order sections:

$sos = [\begin{matrix} b_{01} & b_{11} & b_{21} & 1 & a_{11} & a_{21} \\ b_{02} & b_{12} & b_{22} & 1 & a_{12} & a_{22} \\ ⋮ & ⋮ & ⋮ & ⋮ & ⋮ & ⋮ \\ b_{0 L} & b_{1 L} & b_{2 L} & 1 & a_{1 L} & a_{2 L} \end{matrix}] .$

The rows ofsoscontain the numerator and denominator coefficientsb_ikanda_ikof the cascade of second-order sections ofH(z):

$H (z) = g \prod_{k = 1}^{L} H_{k} (z) = g \prod_{k = 1}^{L} \frac{b_{0 k} + b_{1 k} z^{- 1} + b_{2 k} z^{- 2}}{1 + a_{1 k} z^{- 1} + a_{2 k} z^{- 2}} .$

The number of sections,L, must be greater than or equal to 2. If the number of sections is less than 2,fvtoolconsiders the input to be a numerator vector.

`fvtool(d)`

fvtool(d)opens FVTool and displays the magnitude response of a digital filter,d. Usedesignfiltto generated基于frequency-response specifications.

`fvtool(b1,a1,b2,a2,...,bN,aN)`

fvtool(b1,a1,b2,a2,...,bN,aN)opens FVTool and displays the magnitude responses of multiple filters defined with numeratorsb1, …,bNand denominatorsa1, ...,aN.

`fvtool(sos1,sos2,...,sosN)`

fvtool(sos1,sos2,...,sosN)opens FVTool and displays the magnitude responses of multiple filters defined with second order section matricessos1,sos2, ...,sosN.

`fvtool(Hd)`

fvtool(Hd)opens FVTool and displays the magnitude responses for thedfiltfilter objectHdor the array ofdfiltfilter objects.

`fvtool(Hd1,Hd2,...,HdN)`

fvtool(Hd1,Hd2,...,HdN)opens FVTool and displays the magnitude responses of the filters in thedfiltobjectsHd1,Hd2, ...,HdN.

`h= fvtool(___)`

h= fvtool(___)returns a figure handleh. You can use this handle to interact with FVTool from the command line. SeeControlling FVTool from the MATLAB Command Line.

More About

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Controlling FVTool from the GUI

FVTool has two toolbars:

An extended version of the MATLAB^®plot editing toolbar. The following table shows the toolbar icons specific to FVTool:

Icon	描述
	Restore default view. This view displays buffer regions around the data and shows only significant data. To see the response using standard MATLAB plotting, which shows all data values, useView>Full View.
	Toggle legend
	Toggle grid
	Link toFilter Designer(appears only if FVTool was started fromFilter Designer)
	Toggle Add mode/Replace mode (appears only if FVTool was launched fromFilter Designer)

Analysis toolbar with the following icons:

	Magnitude response of the current filter. See`freqz`and`zerophase`for more information. To see the zero-phase response, right-click they-axis label of the Magnitude plot and selectZero-phasefrom the context menu.
	Phase response of the current filter. See`phasez`for more information.
	Magnitude response and the phase response of the current filter superimposed on one another. See`freqz`for more information.
	Group delay of the current filter. Group delay is the average delay of the filter as a function of frequency. See`grpdelay`for more information.
	Phase delay of the current filter. Phase delay is the time delay the filter imposes on each component of the input signal. See`phasedelay`for more information.
	Impulse response of the current filter. The impulse response is the response of the filter to an impulse input. See`impz`for more information.
	Step response of the current filter. The step response is the response of the filter to a step input. See`stepz`for more information.
	Pole-zero plot, which shows the pole and zero locations of the current filter on thez-plane. See`zplane`for more information.
	Filter coefficients of the current filter, which depend on the filter structure (direct-form or lattice) in a text box. For SOS filters, each section is displayed as a separate filter.
	Detailed filter information.

Linking to Filter Designer

In theFilter Designerapp, selectingView>Filter Visualization Toolor theFull View Analysistoolbar buttonwhen an analysis is displayed starts FVTool for the current filter. You can synchronizeFilter Designerand FVTool with the toolbar button. Any changes made to the filter inFilter Designerare immediately reflected in FVTool.

Two link modes are provided via the toggle toolbar button/:

Replace— removes the filter currently displayed in FVTool and inserts the new filter.
Add— retains the filter currently displayed in FVTool and adds the new filter to the display.

Overlaying a Response

You can overlay a second response on the plot by selectingAnalysis>叠加分析and selecting an available response. A secondy-axis is added to the right side of the response plot. The Analysis Parameters dialog box shows parameters for thex-axis and bothy-axes. SeeDisplay Analysis Parametersfor a sample Analysis Parameters dialog box.

FVTool

描述

More

Open the FVTool

Examples

Magnitude Response of Elliptic Filter

Display Analysis Parameters

FVTool Figure Handle Commands

Magnitude and Phase Response of Bandpass FIR Filter

Related Examples

Programmatic Use

`fvtool(b,a)`

`fvtool(sos)`

`fvtool(d)`

`fvtool(b1,a1,b2,a2,...,bN,aN)`

`fvtool(sos1,sos2,...,sosN)`

`fvtool(Hd)`

`fvtool(Hd1,Hd2,...,HdN)`

`h= fvtool(___)`

More About

Controlling FVTool from the GUI

Linking to Filter Designer

Overlaying a Response

See Also

Apps

Functions

Topics

Introduced before R2006a

Signal Processing Toolbox Documentation

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